Suppose h = f○g. find h'(0) given that f(0) = 8, f '(3) = -4, g(0) = 3, and g '(0) = 9.

i understand that the derivative of h is as follows
h'(x)=f(g')+g(f')
therefore
h'(0)= 8(9)+3(f')
but i can not figure out how to find f'