• Varsity Tutors
    Award-winning private GMAT tutoring
    Register now and save up to $200

    Available with Beat the GMAT members only code

    MORE DETAILS
    Varsity Tutors
  • Veritas Prep
    Free Veritas GMAT Class
    Experience Lesson 1 Live Free

    Available with Beat the GMAT members only code

    MORE DETAILS
    Veritas Prep
  • PrepScholar GMAT
    5 Day FREE Trial
    Study Smarter, Not Harder

    Available with Beat the GMAT members only code

    MORE DETAILS
    PrepScholar GMAT
  • Magoosh
    Magoosh
    Study with Magoosh GMAT prep

    Available with Beat the GMAT members only code

    MORE DETAILS
    Magoosh
  • Economist Test Prep
    Free Trial & Practice Exam
    BEAT THE GMAT EXCLUSIVE

    Available with Beat the GMAT members only code

    MORE DETAILS
    Economist Test Prep
  • EMPOWERgmat Slider
    1 Hour Free
    BEAT THE GMAT EXCLUSIVE

    Available with Beat the GMAT members only code

    MORE DETAILS
    EMPOWERgmat Slider
  • Target Test Prep
    5-Day Free Trial
    5-day free, full-access trial TTP Quant

    Available with Beat the GMAT members only code

    MORE DETAILS
    Target Test Prep
  • e-gmat Exclusive Offer
    Get 300+ Practice Questions
    25 Video lessons and 6 Webinars for FREE

    Available with Beat the GMAT members only code

    MORE DETAILS
    e-gmat Exclusive Offer
  • Kaplan Test Prep
    Free Practice Test & Review
    How would you score if you took the GMAT

    Available with Beat the GMAT members only code

    MORE DETAILS
    Kaplan Test Prep
  • examPAL
    Most awarded test prep in the world
    Now free for 30 days

    Available with Beat the GMAT members only code

    MORE DETAILS
    examPAL

If sq rt (3-2x) = sq rt (2x) + 1.....

This topic has 1 expert reply and 2 member replies
chendawg Master | Next Rank: 500 Posts
Joined
24 Nov 2009
Posted:
163 messages
Followed by:
4 members
Upvotes:
13
Test Date:
7/8
Target GMAT Score:
760
GMAT Score:
660

If sq rt (3-2x) = sq rt (2x) + 1.....

Post Sun Mar 06, 2011 1:57 pm
If sq rt (3-2x) = sq rt (2x) + 1, then 4x^2=

A. 1
B. 4
C. 2 - 2x
D. 4x - 2
E. 6x - 1

Source: OG 12

OA after some discussion.

  • +1 Upvote Post
  • Quote
  • Flag
chendawg Master | Next Rank: 500 Posts
Joined
24 Nov 2009
Posted:
163 messages
Followed by:
4 members
Upvotes:
13
Test Date:
7/8
Target GMAT Score:
760
GMAT Score:
660
Post Wed Mar 09, 2011 8:33 am
OA is indeed E.

I'm not sure if I would be able to figure out to do another square under test conditions, is there a clue for future problems?

  • +1 Upvote Post
  • Quote
  • Flag
anshumishra Legendary Member
Joined
15 Jun 2010
Posted:
543 messages
Followed by:
3 members
Upvotes:
147
Post Sun Mar 06, 2011 3:40 pm
chendawg wrote:
If sq rt (3-2x) = sq rt (2x) + 1, then 4x^2=

A. 1
B. 4
C. 2 - 2x
D. 4x - 2
E. 6x - 1

Source: OG 12

OA after some discussion.
√(3-2x) - √2x = 1; square both sides
=> 3-2x + 2x - 2√(3-2x)(2x) = 1
=> 2√(3-2x)(2x) = 2
=> √(3-2x)(2x) = 1; square both sides
=> (3-2x)*2x = 1
=> 6x - 4x^2 = 1
=> 4x^2 = 6x - 1, E

_________________
Thanks
Anshu

(Every mistake is a lesson learned )

  • +1 Upvote Post
  • Quote
  • Flag

GMAT/MBA Expert

Post Sun Mar 06, 2011 3:30 pm
chendawg wrote:
If sq rt (3-2x) = sq rt (2x) + 1, then 4x^2=

A. 1
B. 4
C. 2 - 2x
D. 4x - 2
E. 6x - 1

Source: OG 12

OA after some discussion.
Since none of the answer choices contains a √, we need to perform algebra that will clear all the √ symbols:

√(3-2x) = √2x + 1

[√(3-2x)]² = (√2x + 1)²

3 - 2x = (√2x + 1)(√2x + 1)

3 - 2x = 2x + √2x + √2x + 1

2 - 2x = 2x + 2√2x

1 - x = x + √2x

1 - 2x = √2x

(1 - 2x)² = (√2x)²

(1 - 2x)(1 - 2x) = 2x

1 - 2x - 2x + 4x² = 2x

4x² = 6x - 1.

The correct answer is E.

_________________
Mitch Hunt
GMAT Private Tutor
GMATGuruNY@gmail.com
If you find one of my posts helpful, please take a moment to click on the "UPVOTE" icon.
Available for tutoring in NYC and long-distance.
For more information, please email me at GMATGuruNY@gmail.com.

  • +1 Upvote Post
  • Quote
  • Flag
Free GMAT Practice Test How can you improve your test score if you don't know your baseline score? Take a free online practice exam. Get started on achieving your dream score today! Sign up now.

Best Conversation Starters

1 lheiannie07 108 topics
2 ardz24 68 topics
3 Roland2rule 65 topics
4 LUANDATO 53 topics
5 VJesus12 52 topics
See More Top Beat The GMAT Members...

Most Active Experts

1 image description GMATGuruNY

The Princeton Review Teacher

146 posts
2 image description Jeff@TargetTestPrep

Target Test Prep

119 posts
3 image description Rich.C@EMPOWERgma...

EMPOWERgmat

114 posts
4 image description Scott@TargetTestPrep

Target Test Prep

101 posts
5 image description EconomistGMATTutor

The Economist GMAT Tutor

85 posts
See More Top Beat The GMAT Experts