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

 It is currently 25 Sep 2016, 19:17

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

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

How many intersects with x-axis does y=x^2+2qx+r have I)

 post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
Senior Manager
Joined: 20 Feb 2006
Posts: 373
Followers: 1

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

How many intersects with x-axis does y=x^2+2qx+r have I) [#permalink]

Show Tags

30 Nov 2006, 17:09
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions

HideShow timer Statistics

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

How many intersects with x-axis does y=x^2+2qx+r have

I) q^2>r

II) r^2>q
VP
Joined: 25 Jun 2006
Posts: 1172
Followers: 3

Kudos [?]: 134 [0], given: 0

[#permalink]

Show Tags

30 Nov 2006, 18:34
A.

(2q)^2 - 4r = 4 (q^2 - r)

all u have to do is to determine q^2 - r is positive or negative or 0.
Manager
Joined: 12 Jul 2006
Posts: 114
Followers: 1

Kudos [?]: 20 [0], given: 0

[#permalink]

Show Tags

30 Nov 2006, 19:29
Sorry - I don't see how you got this equation: (2q)^2-4r, which you simplified to 4(q^2-r). Could you explain further?
_________________

I think I can. I think I can. I think I can.

Senior Manager
Joined: 20 Feb 2006
Posts: 373
Followers: 1

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

[#permalink]

Show Tags

30 Nov 2006, 19:32
I managed to get the correct answer but if this were a PS question - how would you know if there were 2,1 or 0 x intercepts?
Senior Manager
Joined: 20 Feb 2006
Posts: 373
Followers: 1

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

[#permalink]

Show Tags

30 Nov 2006, 19:35
wshaffer wrote:
Sorry - I don't see how you got this equation: (2q)^2-4r, which you simplified to 4(q^2-r). Could you explain further?

Solution of a quadratic equation ax^2 + bx + c is

X = (-b +/- sqrt(b^2 â€“ 4ac))/2a

In this case, a=1 b=2q and c=r

Substituting into the bold (2q)^2 - 4(1*r) = 4q^2 - 4r = 4(q^2 - r)

If you can determine this value of (2q)^2 - 4(1*r) then you know how many intercepts there are - I think.

Tennisball - care to elaborate?
VP
Joined: 25 Jun 2006
Posts: 1172
Followers: 3

Kudos [?]: 134 [0], given: 0

[#permalink]

Show Tags

30 Nov 2006, 20:54
MBAlad wrote:
wshaffer wrote:
Sorry - I don't see how you got this equation: (2q)^2-4r, which you simplified to 4(q^2-r). Could you explain further?

Solution of a quadratic equation ax^2 + bx + c is

X = (-b +/- sqrt(b^2 â€“ 4ac))/2a

In this case, a=1 b=2q and c=r

Substituting into the bold (2q)^2 - 4(1*r) = 4q^2 - 4r = 4(q^2 - r)

If you can determine this value of (2q)^2 - 4(1*r) then you know how many intercepts there are - I think.

Tennisball - care to elaborate?

Yes. all you need to know is b^2 - 4ac.
Senior Manager
Joined: 20 Feb 2006
Posts: 373
Followers: 1

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

[#permalink]

Show Tags

01 Dec 2006, 09:45
But if that were a PS equation what would the resulting value tell us? ie how do we know if there are 0,1 or 2 intercepts?
[#permalink] 01 Dec 2006, 09:45
Display posts from previous: Sort by

How many intersects with x-axis does y=x^2+2qx+r have I)

 post reply Question banks Downloads My Bookmarks Reviews Important topics

 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®.