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

It is currently 11 Jul 2014, 22:02

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
TAGS:
Director
Director
User avatar
Joined: 08 Jun 2004
Posts: 502
Location: Europe
Followers: 1

Kudos [?]: 10 [0], given: 0

GMAT Tests User
In the xy-plane, at what two points does the graph of [#permalink] New post 04 Jul 2006, 02:03
00:00
A
B
C
D
E

Difficulty:

  5% (low)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
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 explain. Thank you.
Manager
Manager
User avatar
Joined: 19 Apr 2006
Posts: 231
Followers: 1

Kudos [?]: 1 [0], given: 0

GMAT Tests User
Re: DS: intersect of x-axis. [#permalink] New post 04 Jul 2006, 07:29
M8 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 explain. Thank you.


st. 1
Insuff, because infinite number of possibilities..

st. 2
y=x^2+(a+b)*x+a*b
if y-intersects at (0,6), then a*b = 6.
so equation is not --> y=x^2+(a+b)*x+6
before I try to combine st. 1, I know that the parabola is going to open up. I feel that this is Insuff.

combine both:
I get y=x^2-1*x+6, but this does not have integer roots for X...
so by the combination of both, it does not intersect the x-axis.

C is my answer... but would E work here?
Intern
Intern
avatar
Joined: 23 Jun 2006
Posts: 26
Followers: 0

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

 [#permalink] New post 04 Jul 2006, 09:25
0 = (x+a)(x+b)

1. insufficient -- too many possibilities
2. can add new information to formula and make it:
0=(x-6)(x+b); since we want to get (x+b) = 0 there are still infinite possibilities.

However, when add information know from (1), can determine value of B. Since we know value of a from (2), we can solve the equation. C.
Manager
Manager
User avatar
Joined: 19 Apr 2006
Posts: 231
Followers: 1

Kudos [?]: 1 [0], given: 0

GMAT Tests User
 [#permalink] New post 04 Jul 2006, 09:34
amartin6165 wrote:
0 = (x+a)(x+b)

1. insufficient -- too many possibilities
2. can add new information to formula and make it:
0=(x-6)(x+b); since we want to get (x+b) = 0 there are still infinite possibilities.

However, when add information know from (1), can determine value of B. Since we know value of a from (2), we can solve the equation. C.


why did you assign a=-6?
if you don't mind, can you tell me what is your value of B?
also are you saying that the function y=(x+a)*(x+b) will have
x-intercepts once you apply both statements?

Thanks
Senior Manager
Senior Manager
avatar
Joined: 09 Aug 2005
Posts: 286
Followers: 1

Kudos [?]: 1 [0], given: 0

GMAT Tests User
Re: DS: intersect of x-axis. [#permalink] New post 04 Jul 2006, 11:52
M8 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 explain. Thank you.


a + b =-1 (infinite possibilities)

ii - ab = 6 (infinite possibilities)

i and ii gives unique answers

So C
Senior Manager
Senior Manager
User avatar
Joined: 07 Jul 2005
Posts: 406
Location: Sunnyvale, CA
Followers: 2

Kudos [?]: 2 [0], given: 0

GMAT Tests User
 [#permalink] New post 04 Jul 2006, 12:08
(C)

I. Cannot calculate a,b given a+b = -1
II. ab = 6 ..Insufficient.


Combining both, we can get values for a, b.
CEO
CEO
User avatar
Joined: 20 Nov 2005
Posts: 2923
Schools: Completed at SAID BUSINESS SCHOOL, OXFORD - Class of 2008
Followers: 13

Kudos [?]: 72 [0], given: 0

GMAT Tests User
 [#permalink] New post 04 Jul 2006, 17:06
C

Graph will intersect x axis at -a and -b. Basically we need to find the value of a and b.

St1: a+b = -1 Can not find values of a and b: INSUFF

St2: 6 = ab Can not find the values of a and b: INSUFF

Combined:
Two distinct equations linear equations of two variables can be solved to get the values of variables.
_________________

SAID BUSINESS SCHOOL, OXFORD - MBA CLASS OF 2008

SVP
SVP
avatar
Joined: 30 Mar 2006
Posts: 1741
Followers: 1

Kudos [?]: 22 [0], given: 0

GMAT Tests User
 [#permalink] New post 04 Jul 2006, 23:25
y=(x+a)(x+b)
y=x^2+x(a+b) +ab

1) a+b is given

Infinte posiibilites hence ab can be anything
2) ab = 6

a+b can be anything.
Not suff

Together

we get a definite value of y for all x hence sufficent
  [#permalink] 04 Jul 2006, 23:25
    Similar topics Author Replies Last post
Similar
Topics:
Experts publish their posts in the topic In the xy-plane, at what two points does the graph metallicafan 1 17 Jul 2012, 06:56
2 In the xy-plane, at what two points does the graph of ttwang56 4 06 Sep 2008, 19:54
In the xy-plane, at what two points does the graph of ldpedroso 1 08 Jun 2008, 11:43
In the xy-plane, at what two points does the graph of peergmatclub 3 07 Jun 2008, 17:13
In the xy-plane, at what two points does the graph of tarek99 11 07 Dec 2007, 06:43
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®.