Questions about the world of GMAT Math from other sources and general math related questions.
lukejosephginter
Students
 
Posts: 1
Joined: Thu Apr 01, 2010 3:17 pm
 

Help?

by lukejosephginter Thu Apr 01, 2010 10:20 pm

y = a(x - p)(x - q), may anyone please define this formula for me?
StaceyKoprince
ManhattanGMAT Staff
 
Posts: 9361
Joined: Wed Oct 19, 2005 9:05 am
Location: Montreal
 

Re: Help?

by StaceyKoprince Mon Apr 05, 2010 9:58 am

Please read (and follow!) forum guidelines before posting. This question should be posted in the General Quant folder.
Stacey Koprince
Instructor
Director, Content & Curriculum
ManhattanPrep
dinesh19aug
Course Students
 
Posts: 37
Joined: Sun Apr 04, 2010 11:52 am
 

Re: Help?

by dinesh19aug Fri Apr 09, 2010 2:42 pm

First multiply (x-p)(x-q)
==> x^2 - xq - px + pq

Next multiple with a
==> ax^2 -axq - apx + apq
thoppae.saravanan
Students
 
Posts: 33
Joined: Fri Mar 19, 2010 9:28 am
 

Re: Help?

by thoppae.saravanan Sat Apr 10, 2010 4:42 pm

Hi,

Not able to get your question - how to define the formula. Could you please elaborate on what you are looking for? If it just expanding the right hand side of the equation then answer above is right.
michael_shaunn
Forum Guests
 
Posts: 10
Joined: Mon Apr 06, 2009 4:09 am
 

Re: Help?

by michael_shaunn Fri Apr 16, 2010 1:30 pm

y=a(x-p)(x-q) represents a quadratic equation where p and q are the respective roots of the given quadratic equation which when substituted in place of x will give y=0.

As far as 'a' is considered, it sets the orientation of the graph for the given quadratic equation i.e. whether the graph for this equation opens in the +ve y direction(if a is positive) or in the -ve y direction(if a is -ve).However, it('a') has no effect on the roots of the given quadratic equation.