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

Redeem

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.

★★★★★5.0559 reviews
Vote for Target Test Prep, Newsweek Readers’ Choice Awards 2026
NEWSWEEK READERS’ CHOICE 2026

BIG NEWS! Target Test Prep has been nominated, and they’d love your vote!

TTP has worked incredibly hard to build the best test prep experience possible, and winning Newsweek’s 2026 Readers’ Choice Award for Best Test Prep would mean a lot to them. If TTP has helped you, they’d be incredibly grateful for your vote. You can vote once each day through September 9.

Vote for TTP
GMATLiveTeach 7 seats left
Chris Peckover
NEXT LIVE COHORT

Oct 13 to Jan 7, 2027

with Chris Peckover

Schedule
Tue, Thu · 8:00 to 10:00 PM ET
Included
40 live hours + 6 months of GMAT OnDemand
  • Live instruction and real-time questions
  • Class recordings and assigned practice
View class & enroll
Limited cohort · enrollment openTarget Test Prep
EALiveTeach 5 seats left
Logan Thompson
EXECUTIVE ASSESSMENT

Sep 6 to Dec 6, 2026

with Logan Thompson

Schedule
Sun · 9:30 AM to 12:30 PM ET
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
Limited cohort · enrollment openTarget Test Prep
GMATOnDemand Start 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 559 reviewsTarget Test Prep

Compare the format, schedule, and included access before enrolling. Prices and seat counts shown reflect the supplied offer details.

Help me with this DS questions frens

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Junior | Next Rank: 30 Posts
Posts: 17
Joined: Mon Dec 01, 2008 8:37 pm
by luckylucky » Tue Feb 24, 2009 1:46 am
In the x-plane, at what two points does the graph of y = (x + a ) ( x + b )
intersect the X-axis ?

(1) a + b = -1

(2) The graph intersects the y - axix at (0 , -6)


As usual, OA after some discussion :D
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Data Sufficiency |
User avatar
Site Admin
Posts: 2567
Joined: Thu Jan 01, 2009 10:05 amFollowed by: 550 members
Thanked: 712 times
GMAT Score:770

by DanaJ » Tue Feb 24, 2009 2:15 am
Intersecting the X-axis means that y = 0. This is accomplished when x is either -a or -b. So in order to solve this problem, you need to know a and b.
y will also be x^2 + (a +b)x + ab.
1. a + b = -1 is not enough to find a and b, so this one is insufficient
2. this tells us that point (0, -6) is on the graph or that -6 = ab. Again, this is not enough to solve for a and b, since you have two unknowns and only one equation.

But put the two together and you can solve the problem. Notice that -6 is -3*2, which will be a and b (since it is consistent with a + b = -1), so we have solved the problem.

I'd go with C.

EDIT: Thank you, missed that.
Last edited by DanaJ on Tue Feb 24, 2009 10:11 am, edited 1 time in total.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 45
Joined: Sun Nov 30, 2008 8:41 pm
Thanked: 4 times

by mrsmarthi » Tue Feb 24, 2009 9:55 am
DanaJ wrote:Intersecting the X-axis means that y = 0. This is accomplished when x is either -a or -b. So in order to solve this problem, you need to know a and b.
y will also be x^2 + (a +b)x + ab.
1. a + b = -1 is not enough to find a and b, so this one is insufficient
2. this tells us that point (0, -6) is on the graph or that 0 = 36 - 6(a + b) + ab. Again, this is not enough to solve for a and b, since you have two unknowns and only one equation.

But put the two together and you get that 0 = 36 + 6 + ab or that ab = - 42. Notice that -42 is -7*6, which will be a and b (since it is consistent with a + b = -1), so we have solved the problem.

I'd go with C.
I will agree with the approach. But solutioning(which obviously is not needed is little incorrect)

2. this tells us that point (0, -6) is on the graph or that x = 0 and y = -6 ==> solving for x and y, we get ab = -6. Again, this is not enough to solve for a and b, since you have two unknowns and only one equation.

But putting together we have,

a+b = -1 and ab = -6. Two distinct eqs and two unknowns. So we should be able to get solve for X intercepts.

I will go with C.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Junior | Next Rank: 30 Posts
Posts: 17
Joined: Mon Dec 01, 2008 8:37 pm

by luckylucky » Tue Feb 24, 2009 6:09 pm
Thank u guys ...

The OA is C
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1