posted by Hannah .
Find the critical values of P(x)
the answer was p=244-7x+8x-x^2/4
p=-x^2/4 + x + 244
p'= -x/2 +1 = 0
My question is, I do not understand how they got -7x + 8x at the beginning. I know (28)(8)=244 but I do not get the rest.