GMAT Math : Algebra

Study concepts, example questions & explanations for GMAT Math

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Example Questions

Example Question #1181 : Gmat Quantitative Reasoning

 is the multiplicative inverse of  is the additive inverse of . Which of the following is equal to the expression

regardless of the values of the variables?

Possible Answers:

 must be an undefined quantity

Correct answer:

Explanation:

The multiplicative inverse of a number is the number which, when multiplied by that number, yields product 1. Since  is the multiplicative inverse of , then 

, or .

The additive inverse of a number is the number which, when added to that number, yields sum 0. Since  is the additive inverse of 

 

It follows that

Any nonzero number raised to the power of 0 is equal to 1. Therefore, 

, the correct choice.

Example Question #1181 : Problem Solving Questions

 is the additive inverse of  is the multiplicative inverse of . Which of the following is equal to the expression

regardless of the values of the variables?

Possible Answers:

 is an undefined quantity.

Correct answer:

Explanation:

The additive inverse of a number is the number which, when added to that number, yields sum 0. Since  is the additive inverse of 

, or 

The multiplicative inverse of a number is the number which, when multiplied by that number, yields product 1. Since  is the multiplicative inverse of , then 

.

It follows that

, the correct response.

Example Question #1183 : Gmat Quantitative Reasoning

 is the multiplicative inverse of  is the additive inverse of . Which of the following is equal to the expression

regardless of the values of the variables?

Possible Answers:

 is an undefined quantity.

Correct answer:

Explanation:

The multiplicative inverse of a number is the number which, when multiplied by that number, yields product 1. Since  is the multiplicative inverse of , then 

.

The additive inverse of a number is the number which, when added to that number, yields sum 0. Since  is the additive inverse of  , 

, or .

It follows that

, the correct response.

Example Question #81 : Understanding Exponents

 is the additive inverse of the multiplicative inverse of  is the additive inverse of the multiplicative inverse of . Which of the following is equal to the expression

regardless of the values of the variables?

Possible Answers:

 is an undefined quantity

Correct answer:

Explanation:

The additive inverse of a number is the number which, when added to that number, yields sum 0; the multiplicative inverse of a number is the number which, when multiplied by that number, yields product 1.

Let  be the multiplicative inverse of . Then 

, or, equivalently, .

 is the additive inverse of this number, so

By similar reasoning, , and

Example Question #81 : Exponents

Which of the following is equal to  ?

Possible Answers:

Correct answer:

Explanation:

Divide:

Substitute:

 

 

Example Question #82 : Exponents

 is the additive inverse of  is the multiplicative inverse of . Which of the following is equal to the expression

regardless of the values of the variables?

Possible Answers:

 must be an undefined quantity.

Correct answer:

Explanation:

The additive inverse of a number is the number which, when added to that number, yields sum 0. Since  is the additive inverse of 

The multiplicative inverse of a number is the number which, when multiplied by that number, yields product 1. Since  is the multiplicative inverse of , then 

, or .

It follows that

.

0 raised to any nonzero power is equal to 0, and  must be nonzero, so

, the correct response.

Example Question #84 : Understanding Exponents

 is the additive inverse of  is the additive inverse of . Which of the following is equal to the expression

regardless of the values of the variables?

Possible Answers:

 must be an undefined quantity

Correct answer:

 must be an undefined quantity

Explanation:

The additive inverse of a number is the number which, when added to that number, yields sum 0. Since  is the additive inverse of  and  is the additive inverse of 

and 

,

which is an undefined expression.

Example Question #1 : Solving Inequalities

How many integers \dpi{100} \small (x) can complete this inequality?

7< 2x-3 <15

Possible Answers:

\dpi{100} \small 4

\dpi{100} \small 5

\dpi{100} \small 6

\dpi{100} \small 9

\dpi{100} \small 3

Correct answer:

\dpi{100} \small 3

Explanation:

7< 2x-3 <15

3 is added to each side to isolate the \dpi{100} \small x term:

10< 2x <18

Then each side is divided by 2 to find the range of \dpi{100} \small x:

5< x <9

The only integers that are between 5 and 9 are 6, 7, and 8.

The answer is 3 integers.

Example Question #2 : Solving Inequalities

Solve 5 < 3x + 10 \leq 16.

Possible Answers:

Correct answer:

Explanation:

5 < 3x + 10 \leq 16

Subtract 10: -5 < 3x \leq 6

Divide by 3: -5/3 < x \leq 2

We must carefully check the endpoints.   is greater than  and cannot equal , yet  CAN equal 2.  Therefore  should have a parentheses around it, and 2 should have a bracket:  is in

 

Example Question #1 : Inequalities

Solve .

Possible Answers:

(- \infty , -2)

(2, \infty )

(-2, \infty )

[-2, \infty ]

[-2, \infty )

Correct answer:

(-2, \infty )

Explanation:

Subtract 3 from both sides:

Divide both sides by :

Remember: when dividing by a negative number, reverse the inequality sign!

Now we need to decide if our numbers should have parentheses or brackets.   is strictly greater than , so  should have a parentheses around it.  Since there is no upper limit here,  is in (-2, \infty )

Note: Infinity should ALWAYS have a parentheses around it, NEVER a bracket.

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