Math Help Forum - View Single Post - Algebra with pq-formula

liljeros · #1 May 22nd, 2008, 11:08 AM

Hello! I am currently having a homework for tomorrow with pretty advanced tasks, for me atleast, that I should solve. I have though got stuck on some of them but there is one in perticular that i have no idea how to solve and I was hoping that you might help me out with this. I start with writing the task.
(It is in Swedish so I am going to try to translate it the best i can)

a) Show that if an Quadratic equation has the roots $x_{1}=a x_{2}=b$ then the equation is $x^2-(a+b)x+ab=0$

b) Solve the Equation above and show that is has the solutions $x_{1}=a x_{2}=b$

I am quite sure that you need to use the pq-formula for this one but then you get $x=\frac{(a+b)}{2} \pm \sqrt{-(\frac{(a+b)}{2})^2}-ab$

This in my eyes does not say much.
If someone is willing to help me out here I'm very glad!
Thanks in advance!
//Rickard Liljeros

PS. I didn't put this in urgent help section since I maybe after this problem will ask for some other algebra help and thought it would be unnecessary to start a new thread for each one.