GRE Prep Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.
Customized
for You
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
If |3x| is different from two, what is the value of
[#permalink]
22 Apr 2019, 09:05
22 Apr 2019, 09:05
Expert Reply
00:00
Question Stats:
77% (00:52) correct
22% (01:03) wrong based on 74 sessions
Hide Show timer Statistics
If \(|3x| \neq 2\), what is the value of \(\frac{9x^2-4}{3x+2} - \frac{9x^2-4}{3x-2}\) ?
A. -9
B. -4
C. 0
D. 4
E. 9
A. -9
B. -4
C. 0
D. 4
E. 9
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
Re: If |3x| is different from two, what is the value of
[#permalink]
06 Jun 2019, 07:13
06 Jun 2019, 07:13
1
Carcass wrote:
If \(|3x| \neq 2\), what is the value of \(\frac{9x^2-4}{3x+2} - \frac{9x^2-4}{3x-2}\) ?
A. -9
B. -4
C. 0
D. 4
E. 9
A. -9
B. -4
C. 0
D. 4
E. 9
GIVEN: \(\frac{9x^2-4}{3x+2} - \frac{9x^2-4}{3x-2}\)
Factor both numerators: \(\frac{(3x+2)(3x-2)}{3x+2} - \frac{(3x+2)(3x-2)}{3x-2}\)
Simplify both fractions: \((3x-2) - (3x+2)\)
Simplify again: \(-4\)
Answer: B
Cheers,
Brent
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
Re: If |3x| is different from two, what is the value of
[#permalink]
06 Jun 2019, 07:17
06 Jun 2019, 07:17
3
Carcass wrote:
If \(|3x| \neq 2\), what is the value of \(\frac{9x^2-4}{3x+2} - \frac{9x^2-4}{3x-2}\) ?
A. -9
B. -4
C. 0
D. 4
E. 9
A. -9
B. -4
C. 0
D. 4
E. 9
FASTER APPROACH
Notice that we're asked to evaluate the expression.
Since all of the answer choices are actual numbers, it must be the case that the expression evaluates to be one of the answer choices FOR ALL VALUES OF X
So, let's plug in a nice value for x (one that will make it super easy to evaluate the expression)
How about x = 0
The expression becomes: \(\frac{9(0)^2-4}{3(0)+2} - \frac{9(0)^2-4}{3(0)-2}\)
Evaluate numerators and denominators to get: \(\frac{-4}{2} - \frac{-4}{-2}\)
Evaluate more to get: \(-2 - 2\)
Evaluate to get: \(-4\)
Answer: B
Cheers,
Brent
