I have this problem that seems relatively easy but i seem to be messing up somewhere.
First i find x-ints/y-ints
x=0 x=3 x=-3
Now the troubling part
Critical Point: F'(x)=0
I use simple quadratic formula and get x values of 18 and -18 (these values don't seem correct) i can't seem to find out what i am doing wrong, any help on this is greatly appreciated.