I was asked to solve this problem, I'm not sure how 4 turns into (4+h) and then it says 8h^2+64h+128.

f ( x + h) - f(x) By determining f'(x) = lim h-0 h find f'(4) for the given function f(X) = 8x4 To use the given definition of the derivative, first find f(x + h) and f(x) using an x-value of 4. Substitute (4 + h) for x in the function f(x) = 8x- to find f(x + h) f(x + h) = f(4 + h)= 8h-+ 64h+ 128 Substitute 4 for x in the function f(X) = 8x- to find f(x ). f(x) =f(4) = 128 (Simplify your