BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem
TTP OnDemand GMAT Video Course
Featured Course

Target Test Prep GMAT OnDemand

Scott Woodbury-Stewart’s private virtual classroom — 400 hours of master-class video lessons for the GMAT Focus Edition.

  • 715+ score guarantee — highest in the industry (99th percentile)
  • 52 chapters · 1,500+ lessons · 4,000+ practice questions
  • 400 hours of video · 1,500+ instructor-led HD smartboard lessons
  • 300,000+ students accepted to Harvard, Stanford, Wharton, Booth & Sloan & more
  • 24/7 live support + weekly Zoom office hours with GMAT instructors
  • TTP AI Assist — 24/7 AI-powered virtual tutor for instant help
  • 1,200+ flashcards + AI-powered study assistant & daily calendar
  • OnDemand, LiveTeach & GMAT Bootcamp formats available
  • Also: GRE, SAT Math & Executive Assessment courses
  • MBA Admissions Consulting now available
  • 🏆 2025 EdTech Breakthrough Award: Test Prep Solution Provider of the Year
  • 200,000+ students served
  • 5-day free trial — $0 to start, no auto-billing, cancel anytime
★★★★★ 5.0 (559 reviews)
130-pt guarantee
$0 to start then $127/mo
Start Free 5-Day Trial Read 559 Reviews →

If a≠b, and a2/(a-b)=b, which of the following could be a?

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
User avatar
Elite Legendary Member
Posts: 3991
Joined: Fri Jul 24, 2015 2:28 amFollowed by: 37 members
Location: Las Vegas, USA
Thanked: 19 times
by Max@Math Revolution » Thu Feb 01, 2018 12:29 am
[GMAT math practice question]

If a≠b, and $$\frac{a^2}{\left(a-b\right)}=b$$ , which of the following could be a?

A. -1
B. 0
C. 1
D. 2
E. a does not exist
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Problem Solving |
Senior | Next Rank: 100 Posts
Posts: 82
Joined: Mon Jan 15, 2018 2:01 am

by DrMaths » Thu Feb 01, 2018 9:31 am
a2/(a-b)=b
a2 = b(a-b)
a2 -ba +b2 = 0
which can not be factorised, so a does not exist
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Elite Legendary Member
Posts: 3991
Joined: Fri Jul 24, 2015 2:28 amFollowed by: 37 members
Location: Las Vegas, USA
Thanked: 19 times

by Max@Math Revolution » Sun Feb 04, 2018 5:05 pm
=>
a^2/(a-b)=b
=> a^2=b(a-b)
=> a^2=ab - b^2
=> a^2 - ab + b^2 = 0
Since a≠b, one of a and b is not zero.
If a ≠ 0 or b ≠ 0, a^2 - ab + b^2 cannot be zero for the following reason:
a^2 - ab + b^2 = a^2 - 2a(b/2) + b^2 = a2 - 2a(b/2) + b^2/3 + (3/4)b^2
= ( a - b/2)^2 + (3/4)b^2 > 0
Thus, there is no pair of real numbers (a,b) satisfying the equation a^2 - ab + b^2 = 0.

Therefore, a cannot exist, and the answer is E.
Answer: E
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1