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quadratic formula
Posted:
Oct 17, 2012 9:14 PM


Hi,
I have a little problem that I have not been able to get to the form required. I may need some help.
here is the problem:
if p(x) = ax^2+bx+c is a second degree polynomial, then prove
p(x) = a(x+b/2a)^2  ((b^2  4ac)/2a)
Here I know the roots of the equation for the quadratic equation is x=(b+sqrt(b^24ac))/2a and the negative of the radicand and also x=b/2a is the vertex
Which root is substituted to get the above form. Or in other words, how do I determine whether I use the negative or the positive radicand in the above equation to get the form shown above. I have simplified it all known ways but cannot seem to get it to that form. Am I barking up the wrong tree here?
thanks
s



