calculus question

Question

Use the given information to find f '(3).

f(x) = g(x)h(x)

g(3) = 7 and g'(3) = 8

h(3) = 2 and h'(3) = -1

Answer 1

f(x) = g(x)h(x)

g(3) = 7 and g'(3) = 8

h(3) = 2 and h'(3) = -1

f'(x) = g(x)h'(x) + g'(x)h(x)

f'(3) = g(3)h'(3) + g'(3)h(3) = 7(-1) + 8(2) = -7 + 16 = 9