Thread: [SOLVED] Quadratic formula??

please help!
f(x) = X[squared] -Kx + 9 , where K is a constant.

find the set values for K for which the equation f(x) = 0 has no real solutions.

and

given that k=4

express f(x) in the form (x - p)2 + q, where p and q are constants to be found.

thanks...

#1: Remember the discriminant?
Given the quadratic , if then there are no real solutions to .

So we must find when:

Can you solve this?

#2: where

We must complete the square. So we take the coefficient of , divide it by 2, square it, and add+subtract it (remember, it's an equation so we can't randomly change one side):


Can you finish?

so would it be:

1: -6<k<6

and

2: (x + 2)2 + 5

?

thanks