## For all integers $$a$$ and $$b,$$ $$a\%b = (a + b)(a - b).$$ If $$5\%x = 9,$$ then which of the following could be a val

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### For all integers $$a$$ and $$b,$$ $$a\%b = (a + b)(a - b).$$ If $$5\%x = 9,$$ then which of the following could be a val

by VJesus12 » Tue Sep 22, 2020 7:25 am

00:00

A

B

C

D

E

## Global Stats

For all integers $$a$$ and $$b,$$ $$a\%b = (a + b)(a - b).$$ If $$5\%x = 9,$$ then which of the following could be a value of $$x?$$

A. -4
B. -3
C. 2
D. 3
E. 6

Answer: A

Source: Veritas Prep

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### Re: For all integers $$a$$ and $$b,$$ $$a\%b = (a + b)(a - b).$$ If $$5\%x = 9,$$ then which of the following could be a

by swerve » Tue Sep 22, 2020 11:35 am
VJesus12 wrote:
Tue Sep 22, 2020 7:25 am
For all integers $$a$$ and $$b,$$ $$a\%b = (a + b)(a - b).$$ If $$5\%x = 9,$$ then which of the following could be a value of $$x?$$

A. -4
B. -3
C. 2
D. 3
E. 6

Answer: A

Source: Veritas Prep
Given $$a\%b = (a + b)(a - b)$$ and $$5\% x = 9$$, we have

$$5\% x = (5+x) \cdot (5-x) = 25 - x^2$$

So, $$25 -x^2 = 9 \Longrightarrow x^2 = 16 \Longrightarrow x = \pm 4$$

Therefore, the correct answer is A

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### Re: For all integers $$a$$ and $$b,$$ $$a\%b = (a + b)(a - b).$$ If $$5\%x = 9,$$ then which of the following could be a

by Scott@TargetTestPrep » Fri Sep 25, 2020 1:24 pm
VJesus12 wrote:
Tue Sep 22, 2020 7:25 am
For all integers $$a$$ and $$b,$$ $$a\%b = (a + b)(a - b).$$ If $$5\%x = 9,$$ then which of the following could be a value of $$x?$$

A. -4
B. -3
C. 2
D. 3
E. 6

Answer: A

Solution:

Translating 5%x = 9 into a regular equation, we have:

(5 + x)(5 - x) = 9

25 - x^2 = 9

16 = x^2

x = 4 or -4

Answer: A

Scott Woodbury-Stewart
Founder and CEO
scott@targettestprep.com

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