Live GMAT classes with Target Test Prep start Nov 21 and Nov 22. First class free.

See classes
Target Test Prep · GMAT

Choose how you want to prepare

Learn live with an expert or move at your own pace. Every option includes the complete TTP study system.

Newsweek Readers’ Choice Awards 2026 winner: Target Test Prep, #1 Test Prep

Target Test Prep was voted #1 Best Test Prep in the 2026 Newsweek Readers’ Choice™ Awards.

★★★★★5.0563 reviews
GMATLiveTeachStarts Nov 22
Josh Braslow, Target Test Prep GMAT expert
LIVE ONLINE CLASSES

Get Ready for GMAT Test Day Faster with Live Online Classes

with Josh Braslow, 20+ years in test prep

Nov 22 · Josh Braslow
Sun · 9:30 AM to 12:30 PM ET
Included
40 hours of live online classes + 6 months of TTP OnDemand
  • Attend the first class for free
  • Every class is recorded, so you never fall behind
View classes & enroll
Limited seats availableTarget Test Prep
EALiveTeachOnDemandStart anytime
EXECUTIVE ASSESSMENT

Target Test Prep EA OnDemand

Self-paced EA prep. Study on your schedule.

EXECUTIVE ASSESSMENT

with

165+ EA score guarantee
$05-day trial no automatic billing
Schedule
Included
40 hours of live online classes plus six months of access to the complete TTP EA OnDemand course.
  • 165+ EA Score Guarantee
  • 4,100+ Quant, Verbal, and Integrated Reasoning practice questions
  • 400+ hours of in-depth video lessons
  • 3,000+ step-by-step video solutions
View EA class & enroll Start free 5-day trial
Limited cohort · enrollment openTrial includes full course accessTarget Test Prep
GMATOnDemandStart anytime
SELF-PACED MASTERCLASS

Target Test Prep GMAT OnDemand

Complete access from day one. Study on your schedule.

715+ score guarantee
$0to start then $127/mo
  • Personalized study plan and analytics
  • Thousands of lessons and practice questions
Start free 5-day trial
Read 563 reviewsTarget Test Prep

What is the value of 2x^2 - 2.4x - 1.7 for x = 0.7?

Expert replies
Post new topic Post Reply
Subscribe topic
Previous Topic Next Topic
Senior | Next Rank: 100 Posts
Posts: 40
Joined: Sat Jul 18, 2009 1:11 pm
Thanked: 4 times
GMAT Score:640
by ironsferri » Thu Jun 17, 2010 10:27 am
What is the value of 2x^2 - 2.4x - 1.7 for x = 0.7?

(A) -0.72
(B) -1.42
(C) -1.98
(D) -2.40
(E) -2.89


What would be the strategy here?

Thank you
Top
Join the discussion
Source: — Problem Solving |
User avatar
Legendary Member
Posts: 1893
Joined: Sun May 30, 2010 11:48 pmFollowed by: 7 members
Thanked: 215 times

by kvcpk » Thu Jun 17, 2010 10:42 am
Answer is D
Top
Join the discussion
User avatar
Legendary Member
Posts: 1893
Joined: Sun May 30, 2010 11:48 pmFollowed by: 7 members
Thanked: 215 times

by kvcpk » Thu Jun 17, 2010 10:53 am
ironsferri wrote: What would be the strategy here?
Thank you
when x is in between 0 an 1, x^2 will be less than x.
so 2x^2 < 2.4x
so 2x^2 - 2.4x will be negative.
neg value -1.7 = value much less than 1.7. so A, B are out.

next, 2x^2 - 2.4x = 2x(x-1.2) = 2x(0.7-1.2) = -x = -0.7

so answer is -0.7 - 1.7 = -2.4
Top
Join the discussion
User avatar
GMAT Instructor
Posts: 3224
Joined: Tue Jan 08, 2008 2:40 pmFollowed by: 614 members
Location: Toronto
Thanked: 1710 times
GMAT Score:800

by Stuart@KaplanGMAT » Thu Jun 17, 2010 11:17 am
ironsferri wrote:What is the value of 2x^2 - 2.4x - 1.7 for x = 0.7?

(A) -0.72
(B) -1.42
(C) -1.98
(D) -2.40
(E) -2.89


What would be the strategy here?

Thank you
Brute force is probably quickest - just substitute in for x. If you're comfortable with the math, it's a 15-30 second question.

2*(.7^2) - 2.4(.7) - 1.7 = 2*.49 - 1.68 - 1.7 = .98 - 3.38 = -2.4... choose (D).
Image

Stuart Kovinsky | Kaplan GMAT Faculty | Toronto

Kaplan Exclusive: The Official Test Day Experience | Ready to Take a Free Practice Test? | Kaplan/Beat the GMAT Member Discount
BTG100 for $100 off a full course
Top
Join the discussion
User avatar
Legendary Member
Posts: 1893
Joined: Sun May 30, 2010 11:48 pmFollowed by: 7 members
Thanked: 215 times

by kvcpk » Thu Jun 17, 2010 11:25 am
From my above post.. Iwould say.. best way to tackle is

2x^2 - 2.4x = 2x(x-1.2) = 2x(0.7-1.2) = -x = -0.7

so answer is -0.7 - 1.7 = -2.4
Top
Join the discussion
Senior | Next Rank: 100 Posts
Posts: 40
Joined: Sat Jul 18, 2009 1:11 pm
Thanked: 4 times
GMAT Score:640

by ironsferri » Thu Jun 17, 2010 11:30 am
Thanks guys for both your input - I think they are both very valuable !

Just a quick follow up question....may sound lame but why multiplying all for 10 (to make them all integers) doesn't work?

Thank you

C
Top
Join the discussion
User avatar
Legendary Member
Posts: 1893
Joined: Sun May 30, 2010 11:48 pmFollowed by: 7 members
Thanked: 215 times

by kvcpk » Thu Jun 17, 2010 11:41 am
ironsferri wrote:Thanks guys for both your input - I think they are both very valuable !

Just a quick follow up question....may sound lame but why multiplying all for 10 (to make them all integers) doesn't work?

Thank you

C
You can multiply the equation by 10 and then divide the result by 10.
But you cannot multiply x by 10. because x^2, x in the eqtn will be different when x is multiplied by 10.
Top
Join the discussion
Senior | Next Rank: 100 Posts
Posts: 40
Joined: Sat Jul 18, 2009 1:11 pm
Thanked: 4 times
GMAT Score:640

by ironsferri » Fri Jun 18, 2010 9:45 am
That's why - you would assume you could unless you pay attention to that ^2.....
Thanks kvcpk!

C-
Top
Join the discussion