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GMAT Preparation Coaching: Algebraic Expressions

  • Writer: Goalisb
    Goalisb
  • Jun 25
  • 15 min read

Welcome back to our GMAT preparation coaching for an absolutely critical, profoundly detailed, and exhaustively precise session in algebraic expressions! Our previous lessons have meticulously dissected the inherent properties of individual arithmetic operations, providing you with a foundational understanding of how numbers behave under addition, subtraction, multiplication, and division. However, in the vast majority of real-world problems and, critically, on the GMAT, you will encounter expressions that combine multiple operations. Without a universally agreed-upon sequence for performing these operations, chaos would ensue, and a single expression could yield multiple, contradictory results.


GMAT Preparation Course

This lesson is meticulously engineered to provide an unparalleled, systematic, and conceptually rigorous breakdown of the Order of Operations, universally known by acronyms like PEMDAS or BODMAS. We will leave no stone unturned, meticulously detailing the precedence of Parentheses/Brackets, Exponents/Orders, Multiplication/Division (as a single, left-to-right tier), and Addition/Subtraction (as another single, left-to-right tier).


Furthermore, as we begin to bridge the gap between pure arithmetic and the more abstract realm of algebra, we will provide a comprehensive Introduction to Algebraic Expressions, defining their components (terms, coefficients, constants, like terms) and demonstrating how our understanding of properties and the order of operations are indispensable for their simplification.


By the conclusion of this exceptionally verbose and rigorous session, your computational precision will be absolute, fostering unwavering confidence, augmented speed, and unparalleled accuracy in evaluating any numerical or algebraic expression, directly contributing to a superior performance on your GMAT examination.


I. The Indispensable Need for Order of Operations: Preventing Mathematical Anarchy

Imagine the following simple expression: 2+3×4.

  • If you perform addition first: (2+3)×4=5×4=20.

  • If you perform multiplication first: 2+(3×4)=2+12=14.

We have two completely different results from the same expression! This ambiguity is unacceptable in mathematics and any field that relies on precise calculation. To eliminate this chaos, mathematicians established a universal convention: the Order of Operations. This is a set of rules that dictate the sequence in which operations must be performed to arrive at a single, correct, and unambiguous result for any given expression.


This universally accepted sequence is commonly remembered by the mnemonics PEMDAS (Parentheses, Exponents, Multiplication, Division, Addition, Subtraction) or BODMAS (Brackets, Orders/Of, Division, Multiplication, Addition, Subtraction). Both acronyms represent the same order of precedence.


II. Dissecting PEMDAS/BODMAS: The Hierarchical Structure of Operations

Let's break down each level of the hierarchy with exhaustive detail and clarifying examples.


A. P/B: Parentheses, Brackets, and Other Grouping Symbols (The Foremost Priority)

  • Priority: Operations enclosed within parentheses (), brackets [], or braces {} must always be performed first. These symbols act as explicit grouping mechanisms, overriding the natural order of operations for the expressions contained within them.

  • Conceptual Insight: Think of grouping symbols as "mini-problems" that must be solved entirely before their results can interact with the rest of the expression. They dictate a localized sequence of operations.

  • Nested Grouping Symbols: If there are multiple layers of grouping symbols (e.g., parentheses inside brackets), you always work from the innermost set outwards.

  • Implied Grouping Symbols:

    • Fraction Bars: The numerator and denominator of a fraction are implicitly grouped. You must calculate the entire value of the numerator and the entire value of the denominator before performing the division.

      • Example: 3−110+2​ is effectively (10+2)÷(3−1).

    • Radical Symbols (Square Roots, Cube Roots, etc.): The expression underneath a radical sign is implicitly grouped. You must evaluate the entire expression under the radical before taking the root.

      • Example: 9+16​ means calculate 9+16 first, then take the square root. 25​=5. (Not 9​+16​=3+4=7).

    • Absolute Value Bars: The expression inside absolute value bars is implicitly grouped. Evaluate the entire expression first, then take its absolute value.

      • Example: ∣5−8∣ means calculate 5−8 first (=−3), then take the absolute value ∣−3∣=3.

  • Exhaustive Detailed Examples:

    • Simple Parentheses: 10−(2+3)

      • Step 1: Perform operation inside parentheses: 2+3=5.

      • Step 2: Substitute the result: 10−5.

      • Step 3: Perform remaining operation: 5.

    • Nested Grouping Symbols: 2×[(5−3)2+4]

      • Step 1 (Innermost Parentheses): 5−3=2.

      • Step 2 (Substitute and Inner Brackets - Exponent): 2×[(2)2+4]→2×[4+4].

      • Step 3 (Inner Brackets - Addition): 4+4=8.

      • Step 4 (Substitute and Final Multiplication): 2×8=16.

    • Implied Grouping (Fraction): 2+415−3​

      • Step 1 (Numerator): 15−3=12.

      • Step 2 (Denominator): 2+4=6.

      • Step 3 (Division): 612​=2.


B. E/O: Exponents, Orders, or Indices (The Power of Scaling)

  • Priority: After addressing grouping symbols, evaluate all exponents (powers and roots).

  • Conceptual Insight: Exponents represent repeated multiplication of a base number. They are a form of hyper-multiplication, and thus take precedence over standard multiplication and division. Roots are simply fractional exponents.

  • Exhaustive Detailed Examples:

    • Positive Base: 42+5

      • Step 1 (Exponent): 42=4×4=16.

      • Step 2 (Addition): 16+5=21.

    • Negative Base (Crucial for Signs): Be extremely careful with negative bases and exponents.

      • (−3)2: The base is (−3), so (−3)×(−3)=9. (The negative sign is inside the grouping).

      • −32: The base is 3, not −3. This means −(3×3)=−9. (The negative sign is applied after the exponentiation). This is a common GMAT trap!

    • Combined with Parentheses: (2+3)2

      • Step 1 (Parentheses): 2+3=5.

      • Step 2 (Exponent): 52=25.

    • Roots: 25​+32

      • Step 1 (Root): 25​=5.

      • Step 2 (Exponent): 32=9.

      • Step 3 (Addition): 5+9=14.


C. MD: Multiplication and Division (The Left-to-Right Equal-Partners)

  • Priority: After exponents, perform all multiplication and division operations. This is a common source of error!

  • Conceptual Insight: Multiplication and division are at the same hierarchical level. They are inverse operations and essentially represent the same fundamental concept (scaling or grouping).

  • The Crucial Rule: Perform from Left to Right. You evaluate these operations as they appear from the left side of the expression to the right side. You do not perform all multiplications first, then all divisions.

  • Exhaustive Detailed Examples:

    • Simple Left to Right: 12÷3×2

      • Step 1 (Leftmost MD: Division): 12÷3=4.

      • Step 2 (Next MD: Multiplication): 4×2=8.

      • Incorrect approach: 12÷(3×2)=12÷6=2. (This is wrong because it applies multiplication before division, which is incorrect unless there are parentheses).

    • Combined Operations: 5×6÷2+10

      • Step 1 (Leftmost MD: Multiplication): 5×6=30.

      • Step 2 (Next MD: Division): 30÷2=15.

      • Step 3 (Remaining AS: Addition): 15+10=25.

    • Involving Negative Numbers: −4×5÷(−2)

      • Step 1 (Leftmost MD: Multiplication): −4×5=−20. (Negative times positive is negative).

      • Step 2 (Next MD: Division): −20÷(−2)=10. (Negative divided by negative is positive).


D. AS: Addition and Subtraction (The Final Stage, Left-to-Right)

  • Priority: After all grouping symbols, exponents, multiplication, and division are completed, perform all remaining addition and subtraction operations.

  • Conceptual Insight: Addition and subtraction are at the same hierarchical level, just like multiplication and division. They are inverse operations and represent fundamental changes in quantity.

  • The Crucial Rule: Perform from Left to Right. Similar to MD, you evaluate these operations as they appear from the left side of the expression to the right side. You do not perform all additions first, then all subtractions.

  • Exhaustive Detailed Examples:

    • Simple Left to Right: 10−4+7

      • Step 1 (Leftmost AS: Subtraction): 10−4=6.

      • Step 2 (Next AS: Addition): 6+7=13.

      • Incorrect approach: 10−(4+7)=10−11=−1. (This is wrong because it applies addition before subtraction, which is incorrect unless there are parentheses).

    • Combined with Negative Numbers: −5+8−12

      • Step 1 (Leftmost AS: Addition): −5+8=3.

      • Step 2 (Next AS: Subtraction): 3−12=−9.


III. Introduction to Algebraic Expressions: The Language of Variables

Having mastered the mechanics of arithmetic operations, we now extend our understanding to algebraic expressions, which form the core language of algebraic problem-solving.

A. Definition of an Algebraic Expression

  • An algebraic expression is a mathematical phrase that can contain numbers, variables (symbols representing unknown values, typically letters like x,y,a,b), and operation signs (+,−,×,÷).

  • Key Distinction: Expression vs. Equation:

    • An expression does not contain an equals sign (=). It represents a single value, and can be simplified or evaluated.

    • An equation does contain an equals sign, stating that two expressions are equal. Equations are solved to find the value(s) of the variable(s) that make the statement true.

  • Examples of Expressions: 5x+7, a2−3b, zy+2​, xyz+1.

  • Examples of Equations: 5x+7=12, a2−3b=0, zy+2​=5.


B. Components of Algebraic Expressions

  1. Terms:

    • Definition: The parts of an expression that are separated by addition (+) or subtraction (−) signs. A term can be a single number, a single variable, or the product of numbers and variables.

    • Examples: In 5x2−7y+10:

      • The terms are: 5x2, −7y, and 10.

      • It's crucial to associate the sign with the term that follows it.

  2. Coefficients:

    • Definition: The numerical factor that multiplies a variable (or variables) in a term.

    • Examples: In 5x2−7y+10:

      • The coefficient of x2 is 5.

      • The coefficient of y is −7.

      • If a variable appears alone (e.g., x), its coefficient is implicitly 1 (e.g., x=1x). If it's −x, the coefficient is −1.

  3. Variables:

    • Definition: Symbols (usually letters) used to represent unknown numerical values. Their values can change.

    • Examples: In 5x2−7y+10, x and y are variables.

  4. Constants:

    • Definition: A term that has a numerical value that does not change. It is a number by itself, without any variables.

    • Examples: In 5x2−7y+10, 10 is a constant.


C. Like Terms: The Foundation for Simplification

  • Definition: Like terms are terms that have the exact same variable (or variables) raised to the exact same power(s). The numerical coefficients do not have to be the same.

  • Conceptual Insight: You can only directly add or subtract "apples with apples" and "oranges with oranges." In algebra, "like terms" are the "apples" and "oranges."

  • Examples of Like Terms:

    • 3x and 7x (Both have x1)

    • −2y2 and 5y2 (Both have y2)

    • 10ab and −3ab (Both have ab)

    • 5 and −12 (Both are constants/numbers)

  • Examples of Unlike Terms:

    • 3x and 3x2 (Different powers of x)

    • 4x and 4y (Different variables)

    • 2ab and 2ac (Different variable combinations)


D. Combining Like Terms: The Power of Reverse Distribution

  • Process: To combine like terms, you add or subtract their numerical coefficients while keeping the common variable part unchanged.

  • Underlying Property: This process is a direct application of the Distributive Property in reverse (also known as factoring).

    • Example: 5x+3x=(5+3)x=8x. Here, x is the common factor being "distributed out" or "factored out."

  • Exhaustive Detailed Examples:

    • Example 1: Simple Combination

      • Simplify: 7a−3a+a

      • Step 1: Identify like terms: All terms are like terms (all have a1).

      • Step 2: Combine coefficients: 7−3+1 (remember a is 1a).

      • Step 3: Perform addition/subtraction from left to right: 7−3=4. Then 4+1=5.

      • Result: 5a.

    • Example 2: Multiple Sets of Like Terms

      • Simplify: 4x+2y−x+5y−3

      • Step 1: Identify and group like terms (mentally or by rearranging using Commutative Property):

        • 'x' terms: 4x and −x (remember x is 1x, and −x is −1x).

        • 'y' terms: 2y and 5y.

        • Constant: −3.

      • Step 2: Combine coefficients for each set of like terms:

        • 'x' terms: 4+(−1)=3. So, 3x.

        • 'y' terms: 2+5=7. So, 7y.

      • Step 3: Write the simplified expression, including the constant.

      • Result: 3x+7y−3.


IV. Applying Order of Operations to Algebraic Expressions: Evaluation and Simplification

The rules of PEMDAS/BODMAS apply rigorously to algebraic expressions, both when substituting numerical values and when simplifying.


A. Evaluating Expressions (Substituting Values)

  • When you are given values for the variables in an expression, you substitute those values into the expression and then use the Order of Operations to calculate a single numerical result.

  • Crucial Tip: When substituting, it's often helpful to place the substituted value in parentheses to avoid sign errors or misinterpretations, especially for negative numbers or when the variable is part of a product or power.

  • Exhaustive Detailed Example:

    • Problem: Evaluate 3x2−2y+5 when x=−2 and y=4.

    • Step 1: Substitute the values into the expression, using parentheses for clarity.

      • 3(−2)2−2(4)+5.

    • Step 2: Apply PEMDAS.

      • P (Parentheses): The numbers inside the parentheses are already simplified.

      • E (Exponents): Evaluate (−2)2. Base is −2. (−2)×(−2)=4.

      • Expression is now: 3(4)−2(4)+5.

      • MD (Multiplication and Division - Left to Right):

        • First multiplication: 3×4=12.

        • Next multiplication: 2×4=8. (Note the original subtraction: it's −8).

      • Expression is now: 12−8+5.

      • AS (Addition and Subtraction - Left to Right):

        • First subtraction: 12−8=4.

        • Next addition: 4+5=9.

    • Result: 9.


B. Simplifying Algebraic Expressions

  • When simplifying algebraic expressions, you apply PEMDAS/BODMAS to perform operations (like distribution) and then combine like terms. This does not result in a single numerical answer but rather a simpler algebraic expression.


  • Exhaustive Detailed Example:

    • Problem: Simplify 2x+5(x−y)−3y+(x+2y)

    • Step 1: Address Parentheses/Grouping Symbols using the Distributive Property.

      • For 5(x−y): Distribute 5. 5⋅x=5x. 5⋅(−y)=−5y. Result: 5x−5y.

      • For (x+2y): No coefficient to distribute other than an implicit 1. So, simply remove parentheses: x+2y.

    • Step 2: Rewrite the entire expression with the expanded parts.

      • 2x+5x−5y−3y+x+2y.

    • Step 3: Identify and group like terms (mentally or by rewriting).

      • 'x' terms: 2x, +5x, +x (which is 1x).

      • 'y' terms: −5y, −3y, +2y.

    • Step 4: Combine coefficients for each set of like terms.

      • 'x' terms: 2+5+1=8. So, 8x.

      • 'y' terms: −5+(−3)+2.

        • −5+(−3)=−8.

        • −8+2=−6. So, −6y.

    • Step 5: Write the final simplified expression.

      • 8x−6y.

    • Result: 8x−6y.


V. GMAT Relevance & Strategic Insights: Mastering the Quantitative Language

Order of operations and algebraic expressions are not just topics; they are the fundamental language of GMAT Quant.

  • Ubiquitous Application: Every single Quantitative problem on the GMAT, whether it involves number properties, algebra, geometry, word problems, or data interpretation, will at some point require you to apply the order of operations correctly.

  • Avoiding Careless Errors: Incorrect application of PEMDAS/BODMAS is a prime source of preventable errors, especially under time pressure. Mastering it prevents these "silly mistakes."

  • Efficient Simplification: Being adept at combining like terms and distributing allows you to condense complex expressions into simpler forms, making subsequent calculations or comparisons easier. This is vital for speed.

  • Function Evaluation: When evaluating functions (e.g., f(x)=2x2−x+1), you substitute the input value for x and then must follow PEMDAS to get the correct output.

  • Inequalities: Evaluating and simplifying expressions within inequalities also demands strict adherence to the order of operations.

  • Data Sufficiency: Questions involving expressions or equations often test your ability to correctly simplify or evaluate them. An incorrect PEMDAS application could lead to a wrong answer (e.g., thinking a statement is sufficient when it's not due to an error in calculation).


VI. Common Pitfalls: Dissecting Errors and Fortifying Your Defenses

Understanding the typical mistakes is the first step toward flawless execution.

  1. Misunderstanding "Left-to-Right" for MD and AS:

    • The Error: Performing all multiplication before all division, or all addition before all subtraction.

      • Example: 12÷4×3 becomes 12÷12=1 (Incorrect, should be 3×3=9).

      • Example: 10−3+2 becomes 10−5=5 (Incorrect, should be 7+2=9).

    • Why it Happens: Misinterpretation of the PEMDAS/BODMAS acronym as strict sequential steps for M-D and A-S, rather than hierarchical tiers.

    • Defense Strategy: Group them! Mentally or physically write (MD) and (AS) to remind yourself they are equal partners within their tier. Visualize a sweep from left to right. Practice exercises specifically designed to test this left-to-right rule.

  2. Incorrect Handling of Negative Signs with Exponents:

    • The Error: Confusing (−x)n with −xn.

      • Example: −22 evaluated as 4 (Incorrect, should be −4).

    • Why it Happens: Neglecting the parentheses that explicitly define the base of the exponent.

    • Defense Strategy: Parentheses are King! If the negative sign is inside the parentheses, it's part of the base. If it's outside, it's applied after the exponentiation. Always evaluate the power first, then apply the negative if it's external.

  3. Incomplete Distribution / Sign Errors in Distribution:

    • The Error: Not distributing to all terms, or making sign errors, especially with negative factors. (Reiterated from 5.2 due to its critical importance).

    • Why it Happens: Rushing, lack of consistent application.

    • Defense Strategy: Draw Arrows and Slow Down for Negatives. Every term inside the parentheses gets multiplied. For negative distributors, perform sign multiplication explicitly.

  4. Misinterpreting Implied Parentheses (Fractions, Radicals):

    • The Error: Performing division or taking a root before completely evaluating the numerator/denominator or the expression under the radical.

      • Example: 26+4​ evaluated as 6+(4/2)=6+2=8 (Incorrect, should be (6+4)/2=10/2=5).

    • Why it Happens: Not recognizing the implicit grouping effect of fraction bars or radical signs.

    • Defense Strategy: Visualize Parentheses. Mentally (or physically) wrap parentheses around the entire numerator, the entire denominator, and the entire expression under a radical.

  5. Confusing Expressions with Equations:

    • The Error: Attempting to "solve" an expression (e.g., by dividing both sides by a number) or thinking an expression has a single numerical solution when it still contains variables.

    • Why it Happens: Not understanding the fundamental difference between a mathematical phrase (expression) and a mathematical statement of equality (equation).

    • Defense Strategy: Check for the Equals Sign. No equals sign means it's an expression; you can simplify or evaluate it (if variable values are given), but not "solve" it.


VII. Check Your Understanding:

Let's apply these principles with meticulous, exhaustive step-by-step solutions to ensure profound mastery.


  1. Evaluate: 25−42+(10−2×3)÷2

    • Purpose: To apply the full PEMDAS sequence, including nested parentheses and left-to-right operations.

    • Step 1: P (Parentheses/Brackets) - Innermost First.

      • Inside (10−2×3): Multiplication first. 2×3=6.

      • Substitute: (10−6).

      • Inside parentheses: 10−6=4.

      • The expression is now: 25−42+4÷2.

    • Step 2: E (Exponents).

      • Evaluate 42=4×4=16.

      • The expression is now: 25−16+4÷2.

    • Step 3: MD (Multiplication and Division) - Left to Right.

      • Only one MD operation: 4÷2=2.

      • The expression is now: 25−16+2.

    • Step 4: AS (Addition and Subtraction) - Left to Right.

      • First operation from left: 25−16=9.

      • Next operation: 9+2=11.

    • Result: 11.


  2. Simplify the algebraic expression: 7(2a−b)−3(a+4b)+a

    • Purpose: To apply the Distributive Property with positive and negative distribution, and then combine like terms.

    • Step 1: P (Parentheses/Grouping Symbols) - Distribute.

      • For 7(2a−b):

        • 7⋅2a=14a.

        • 7⋅(−b)=−7b.

        • First part becomes: 14a−7b.

      • For −3(a+4b):

        • −3⋅a=−3a.

        • −3⋅4b=−12b. (Negative times positive is negative).

        • Second part becomes: −3a−12b.

    • Step 2: Rewrite the entire expression with the expanded parts.

      • 14a−7b−3a−12b+a.

    • Step 3: (Optional) Convert subtractions to additions of inverses for clarity.

      • 14a+(−7b)+(−3a)+(−12b)+a.

    • Step 4: Identify and group like terms (rearrange using Commutative Property).

      • 'a' terms: 14a, −3a, +a (which is 1a).

      • 'b' terms: −7b, −12b.

      • Expression now looks like: (14a+(−3a)+a)+((−7b)+(−12b)).

    • Step 5: Combine coefficients for each set of like terms.

      • 'a' terms: 14+(−3)+1=11+1=12. So, 12a.

      • 'b' terms: (−7)+(−12)=−19. So, −19b.

    • Step 6: Write the final simplified expression.

      • 12a−19b.

    • Result: 12a−19b.


VIII. Practice Questions: (With Exhaustive, Micro-Step Solutions)

  1. Evaluate the expression: 18÷6×2+(5−3)3

    a) 10

    b) 14

    c) 18

    d) 20

  2. Simplify the expression: x2+5x−3(x2−2x)+7

    a) −2x2+11x+7

    b) 4x2−x+7

    c) −2x2−x+7

    d) 4x2+7x+7

  3. If a=−2 and b=3, evaluate: 2a+ba2−b​

    a) −1/2

    b) 1/2

    c) 7

    d) −7

  4. Which of the following terms are considered "like terms" with 6xy2?

    I. 2xy2

    II. −10y2x

    III. 6x2y

    IV. xy2

    a) I, II, and III only

    b) I, II, and IV only

    c) I, III, and IV only

    d) All of the above


Exhaustive Micro-Step Solutions to Practice Questions:

  1. Evaluate the expression: 18÷6×2+(5−3)3

    • Goal: Apply PEMDAS systematically.

    • Step 1: P (Parentheses).

      • Inside (5−3): 5−3=2.

      • Expression becomes: 18÷6×2+(2)3.

    • Step 2: E (Exponents).

      • Evaluate (2)3=2×2×2=8.

      • Expression becomes: 18÷6×2+8.

    • Step 3: MD (Multiplication and Division) - Left to Right.

      • First operation from left: 18÷6=3.

      • Next operation: 3×2=6.

      • Expression becomes: 6+8.

    • Step 4: AS (Addition and Subtraction) - Left to Right.

      • Perform addition: 6+8=14.

    • Final Answer: b) 14.


  2. Simplify the expression: x2+5x−3(x2−2x)+7

    • Goal: Simplify an algebraic expression involving distribution and combining like terms.

    • Step 1: P (Parentheses) - Distribute.

      • For −3(x2−2x):

        • −3⋅x2=−3x2.

        • −3⋅(−2x). Negative × negative = positive. 3⋅2x=6x. So, +6x.

        • This part becomes: −3x2+6x.

    • Step 2: Rewrite the entire expression with the expanded part.

      • x2+5x−3x2+6x+7.

    • Step 3: (Optional) Convert subtractions to additions of inverses.

      • x2+5x+(−3x2)+6x+7.

    • Step 4: Identify and group like terms.

      • 'x^2' terms: x2 (which is 1x2) and −3x2.

      • 'x' terms: 5x and 6x.

      • Constant: 7.

      • Expression grouping: (x2−3x2)+(5x+6x)+7.

    • Step 5: Combine coefficients for each set of like terms.

      • 'x^2' terms: 1+(−3)=−2. So, −2x2.

      • 'x' terms: 5+6=11. So, 11x.

      • Constant: 7.

    • Step 6: Write the final simplified expression.

      • −2x2+11x+7.

    • Final Answer: a) −2x2+11x+7.


  3. If a=−2 and b=3, evaluate: 2a+ba2−b​

    • Goal: Substitute values and apply order of operations for a fractional expression (implicit grouping).

    • Step 1: Substitute the values of a and b into the expression, using parentheses for a because it's negative.

      • 2(−2)+3(−2)2−3​.

    • Step 2: Evaluate the Numerator (treat as a group/parentheses).

      • E (Exponents): (−2)2=(−2)×(−2)=4.

      • Numerator is now: 4−3.

      • AS (Subtraction): 4−3=1.

      • Numerator result: 1.

    • Step 3: Evaluate the Denominator (treat as a group/parentheses).

      • MD (Multiplication): 2(−2)=−4.

      • Denominator is now: −4+3.

      • AS (Addition): −4+3=−1.

      • Denominator result: −1.

    • Step 4: Perform the final Division (fraction means division).

      • −11​=−1.

    • Final Answer: None of the options match my calculation. Let me re-verify.

      • Numerator: a2−b=(−2)2−3=4−3=1. Correct.

      • Denominator: 2a+b=2(−2)+3=−4+3=−1. Correct.

      • Fraction: 1/(−1)=−1. Correct.

    • Self-Correction/Debugging: Again, my detailed calculation leads to −1, which is not among the options. This suggests an issue with the provided options. I will proceed by stating my calculated answer and noting the discrepancy, as this maintains integrity and demonstrates the correct process.

    Final Answer: (My calculation yields −1. As this is not among the options, there might be an error in the options provided for this specific question.)


  1. Which of the following terms are considered "like terms" with 6xy2?

    I. 2xy2

    II. −10y2x

    III. 6x2y

    IV. xy2

    • Goal: Identify terms that have the exact same variables raised to the exact same powers.

    • Reference Term: 6xy2. This means it has x to the power of 1 (x1) and y to the power of 2 (y2). The order of variables does not matter (xy2 is the same as y2x).

    • Analyze Option I: 2xy2

      • Variables: x1,y2.

      • Matches 6xy2.

      • Conclusion: Like term.

    • Analyze Option II: −10y2x

      • Variables: y2,x1. (Order doesn't matter, so this is equivalent to x1y2).

      • Matches 6xy2.

      • Conclusion: Like term.

    • Analyze Option III: 6x2y

      • Variables: x2,y1.

      • Does not match 6xy2 (powers of x and y are different).

      • Conclusion: Not a like term.

    • Analyze Option IV: xy2

      • Variables: x1,y2. (Implicit coefficient of 1).

      • Matches 6xy2.

      • Conclusion: Like term.

    • Final Selection: Terms I, II, and IV are like terms.

    • Final Answer: b) I, II, and IV only.


IX. Comprehensive Self-Assessment Checklist

This comprehensive, highly granular, and exhaustive checklist is your ultimate diagnostic instrument to unequivocally confirm your profound and unassailable understanding of every single nuance pertaining to the Order of Operations and Algebraic Expressions. Each "Yes" response should reflect an absolute and unwavering confidence in your ability to perform and articulate the concept. If any item elicits a "No," it serves as an unequivocal signal for a critical area demanding immediate, focused, and thorough re-study and dedicated practice.

  • Do you understand the fundamental necessity of the Order of Operations (PEMDAS/BODMAS) to ensure a single, unambiguous result for any mathematical expression?

    • [ ] Yes [ ] No

  • Can you correctly identify and prioritize operations within Parentheses, Brackets, and other explicit grouping symbols (like braces), always working from the innermost outwards?

    • [ ] Yes [ ] No

  • Do you recognize and correctly apply the implicit grouping rules for fraction bars, radical symbols, and absolute value bars, ensuring the expressions within them are evaluated first?

    • [ ] Yes [ ] No

  • Are you consistently accurate in evaluating Exponents (powers and roots), especially when dealing with negative bases and the critical distinction between (−x)n and −xn?

    • [ ] Yes [ ] No

  • Do you rigorously apply the Left-to-Right rule for Multiplication and Division (treating them as operations of equal precedence)?

    • [ ] Yes [ ] No

  • Do you rigorously apply the Left-to-Right rule for Addition and Subtraction (treating them as operations of equal precedence)?

    • [ ] Yes [ ] No

  • Can you correctly articulate the definition of an algebraic expression and clearly distinguish it from an equation?

    • [ ] Yes [ ] No

  • Can you accurately identify the terms, coefficients, variables, and constants within any given algebraic expression?

    • [ ] Yes [ ] No

  • Can you correctly identify "like terms", understanding that they must have the exact same variables raised to the exact same powers?

    • [ ] Yes [ ] No

  • Are you proficient at combining like terms in an algebraic expression, understanding that this process leverages the Distributive Property in reverse?

    • [ ] Yes [ ] No

  • Can you confidently evaluate algebraic expressions by substituting given numerical values for variables and then rigorously following the Order of Operations to compute a single numerical result?

    • [ ] Yes [ ] No

  • Can you efficiently simplify complex algebraic expressions by first applying distribution (using PEMDAS) and then combining all like terms?

    • [ ] Yes [ ] No

  • Do you understand how strict adherence to the Order of Operations is fundamental for accuracy and speed across virtually all GMAT Quantitative problem types?

    • [ ] Yes [ ] No

  • Are you acutely aware of the common pitfalls related to PEMDAS/BODMAS (e.g., L-R errors, negative exponent issues, distribution errors) and do you employ specific, proactive strategies to prevent each one?

    • [ ] Yes [ ] No

 
 
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