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

Root

Expert replies
Post new topic Post Reply
Subscribe topic
Previous Topic Next Topic
Senior | Next Rank: 100 Posts
Posts: 59
Joined: Tue Jun 10, 2008 6:49 pm
Thanked: 2 times
by cartera » Thu Jan 22, 2009 8:16 am
If r and s are root of x^2+bx+c=0, rs<0?
1). b<0
2). c<0

OA B

I dont catch it
Top
Join the discussion
Source: — Data Sufficiency |
Junior | Next Rank: 30 Posts
Posts: 23
Joined: Mon Jan 19, 2009 7:16 pm
Thanked: 1 times

by techwiz » Thu Jan 22, 2009 1:21 pm
To ensure that rs <0, the r and s must be of opposite sign. Which means b^2 - 4c > b^2 [ as per Quadratic equation solution]

Which means c < 0. Hece statement 2 is alone sufficient.
Top
Join the discussion
Master | Next Rank: 500 Posts
Posts: 137
Joined: Thu Jan 08, 2009 1:27 am
Thanked: 7 times

by welcome » Thu Jan 22, 2009 1:32 pm
Solution of x^2+bX+c=0 will be

(-b+(b^2-4c)^1/2)/2 = r
(-b-(b^2-4c)^1/2)/2 = s

so r*s = b^2-(b^2-4c)/4
=> rs = 4c/4 = c

means rs is equal to C.

1) value of b will not affect value of rs - NOT SUff
2) value of C will direclt effect rs - Answer

Answerd : B.
Shubham.
590 >> 630 >> 640 >> 610 >> 600 >> 640 >> 590 >> 640 >> 590 >> 590
Top
Join the discussion
Junior | Next Rank: 30 Posts
Posts: 23
Joined: Mon Jan 19, 2009 7:16 pm
Thanked: 1 times

by techwiz » Thu Jan 22, 2009 2:23 pm
To ensure that rs <0, the r and s must be of opposite sign. Which means b^2 - 4c > b^2 [ as per Quadratic equation solution]

Which means c < 0. Hece statement 2 is alone sufficient.
Top
Join the discussion
Master | Next Rank: 500 Posts
Posts: 160
Joined: Sat Dec 20, 2008 9:12 pm
Thanked: 11 times

Re: Root

by aroon7 » Sat Jan 24, 2009 9:50 am
cartera wrote:If r and s are root of x^2+bx+c=0, rs<0?
1). b<0
2). c<0

OA B

I dont catch it
r*s is product of the roots of this quadratic equation
ie constant term / coeff of x^2
= c
if c is less than 0, then rs < 0
--------------------------
i am back!
Top
Join the discussion
Senior | Next Rank: 100 Posts
Posts: 33
Joined: Sat Jan 17, 2009 3:48 pm
Thanked: 1 times

by GID09 » Thu Jan 29, 2009 1:56 pm
If r and S are the roots of the quadratic equation x^2+bX+C = 0 ...(1)
then (X-r)(X-s)=0
Upon simplification
X^2 -(r+s)x+rs = 0 ....(2)

Comparing (2) with (1)
b= -r-s
c=rs

Case 1
b<0 => -r-s<0 => Implies nothing ...insuff

Case 2
c<0 => rs< 0 => suff

Hence B
Top
Join the discussion