Find all School-related info fast with the new School-Specific MBA Forum

It is currently 01 Sep 2015, 05:12
GMAT Club Tests

Close

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

In the xy-plane, at what two points does the graph of

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
Intern
Intern
avatar
Joined: 27 Mar 2008
Posts: 25
Followers: 0

Kudos [?]: 0 [0], given: 0

In the xy-plane, at what two points does the graph of [#permalink] New post 07 Jun 2008, 17:13
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

In the xy-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-axis at (0,-6)


Please solve this problem and explain ur answers

peer
Manager
Manager
avatar
Joined: 21 Mar 2008
Posts: 244
Followers: 2

Kudos [?]: 21 [0], given: 0

Re: DS 2 - Line interesection [#permalink] New post 07 Jun 2008, 19:26
E

The equation y = (x+a)(x+b) expands into a quadratic with the roots -a and -b. So the question is asking what are the values of a and b and hence the points (a, 0) and (b, 0) are the 2 points of intersection with the x axis.

1. a+b=-1, insuff to find a and b
2. this leads to ab = -6, insuff

1+2
solving for a and b we get -2 and 3 for b and 3 and -2 for a. So, there are multiple possibilities for a and b. Hence E
Manager
Manager
avatar
Joined: 10 Mar 2008
Posts: 67
Followers: 2

Kudos [?]: 25 [0], given: 0

Re: DS 2 - Line interesection [#permalink] New post 07 Jun 2008, 22:53
peergmatclub wrote:
In the xy-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-axis at (0,-6)


Please solve this problem and explain ur answers

peer

C

y=x^2+x(a+b)+ab----------(1)

1)a+b=-1
2)put x=0 in (1) ab=-6

combine

y=x^2+x(-1)-6
for a lne to touch x xis y=0

0=x^2-x-6

solving x=-2,3

points=(-2,0),(3,0)
Manager
Manager
avatar
Joined: 21 Mar 2008
Posts: 244
Followers: 2

Kudos [?]: 21 [0], given: 0

Re: DS 2 - Line interesection [#permalink] New post 08 Jun 2008, 15:06
Found my mistake....thanks Rohit... :wall
Re: DS 2 - Line interesection   [#permalink] 08 Jun 2008, 15:06
Display posts from previous: Sort by

In the xy-plane, at what two points does the graph of

  Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Privacy Policy| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group and phpBB SEO

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.