Last visit was: 15 Nov 2024, 12:48 It is currently 15 Nov 2024, 12:48

Close

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

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GRE score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel
Verbal Expert
Joined: 18 Apr 2015
Posts: 29961
Own Kudos [?]: 36234 [0]
Given Kudos: 25907
Send PM
avatar
Manager
Manager
Joined: 04 Feb 2019
Posts: 204
Own Kudos [?]: 418 [0]
Given Kudos: 0
Send PM
Verbal Expert
Joined: 18 Apr 2015
Posts: 29961
Own Kudos [?]: 36234 [0]
Given Kudos: 25907
Send PM
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Own Kudos [?]: 12189 [1]
Given Kudos: 136
Send PM
Re: For all integers a and b, where a ≠ b [#permalink]
1
Carcass wrote:
For all integers a and b, where \(a ≠ b\), \(a ★ b = \mid ( \frac{a^2 - b^2}{(a - b)} \mid\)

What is the value of 4★2 ?

A. 2
B. 4
C. 6
D. 8
E. 10


One approach is to recognize that we can SIMPLIFY the fraction \(\frac{a^2 - b^2}{(a - b)}\) by first factoring the numerator.

We get: \(|\frac{a^2 - b^2}{(a - b)}| = |\frac{(a+b)(a-b)}{(a - b)}|=|a+b|\)

So, a ★ b = |a + b|
This means: 4 ★ 2 = |4 + 2| = |6| = 6

Cheers,
Brent
Moderator
Moderator
Joined: 02 Jan 2020
Status:GRE Quant Tutor
Posts: 1111
Own Kudos [?]: 961 [1]
Given Kudos: 9
Location: India
Concentration: General Management
Schools: XLRI Jamshedpur, India - Class of 2014
GMAT 1: 700 Q51 V31
GPA: 2.8
WE:Engineering (Computer Software)
Send PM
Re: For all integers a and b, where a b [#permalink]
1
Given that \(a ★ b = |\frac{(a^2 - b^2)}{(a - b)}|\) and we need to find the value of \(4 ★ 2\)

To find \(4 ★ 2\) we need to compare what is before and after ★ in \(4 ★ 2\) and a ★ b

=> We need to substitute a with 4 and b with 2 in a ★ b to get the value of \(4 ★ 2\)

=> \(4 ★ 2 = |\frac{(4^2 - 2^2)}{(4 - 2)}|\) = \(|\frac{16 - 4}{2}|\) = \(|\frac{12}{2}|\) = \(|6|\) = 6
( Watch this video to learn about the Basics of Absolute Value )

So, Answer will be C
Hope it helps!

Watch the following video to learn the Basics of Functions and Custom Characters

Prep Club for GRE Bot
Re: For all integers a and b, where a b [#permalink]
Moderators:
GRE Instructor
78 posts
GRE Forum Moderator
37 posts
Moderator
1111 posts
GRE Instructor
234 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne