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

Quadratic match

Expert replies
by maihuna » Fri Nov 13, 2009 12:32 pm
If b, c, and d are constants and x^2 + bx + c = (x + d)^2 for all values of x, what is the value
of c?
(1) d = 3
(2) b = 6

[spoiler]E/D[/spoiler]
Charged up again to beat the beast :)
Join the discussion
Source: — Data Sufficiency |

Re: Quadratic match

by Ian Stewart » Fri Nov 13, 2009 1:11 pm
maihuna wrote:If b, c, and d are constants and x^2 + bx + c = (x + d)^2 for all values of x, what is the value
of c?
If x^2 + bx + c = (x + d)^2 for *all* values of x, then the equation is certainly true when x=0. Plugging in, we find that c = d^2. So Statement 1 is sufficient.

Now, expanding the right side, and replacing c with d^2:

x^2 + bx + d^2 = x^2 + 2dx + d^2
bx = 2dx
b = 2d

So if we know b, we can find d, and therefore find c, and Statement 2 is also sufficient.
For online GMAT math tutoring, or to buy my higher-level Quant books and problem sets, contact me at ianstewartgmat at gmail.com

ianstewartgmat.com
Join the discussion

by Lance123 » Fri Nov 13, 2009 9:35 pm
If b, c, and d are constants and x^2 + bx + c = (x + d)^2 for all values of x, what is the value
of c?
(1) d = 3
(2) b = 6


Is it possible to look at it from this point of view.

Taking statement 1 Alone:
d=3

x^2 + bx + c = (x + d)^2 , d=3
x^2 + bx + c = (x + 3)^2
expanding the RHS and comparing coefficients, it is possible to determine c

So 1 is sufficient.

Taking statement 2
b = 6
x^2 + bx + c = (x + d)^2

x^2 + 6x + c = (x + d)^2
x^2 + 6x + c = x^2 + 2dx + d^2

comparing coefficients,

2d=6
d=3

c= d^2
c= (3)^2
c=9

Statement 2 is Sufficient.
Join the discussion

by notts5 » Sun Nov 15, 2009 1:08 am
But we know by comparing the two sides that c=d^2 and Statement one provides us with the value of d=3.

Therefore, c=d^2=(3)^2=9

Hence, Statement 1 is sufficient.
Join the discussion