Given f(5)=3, f′(5)=7, g(5)=−1, and g′(5)=8, find the values of the following.

Question

I know that (b) will equal -31 ! I am unable to answer the (a) part of this equation. I have tried several different methods but my answer continues to come out wrong. Will you please take a look over this problem and help me answer the (a) section properly? :) Thank you~

Given f(5)=3, f′(5)=7, g(5)=−1, and g′(5)=8, find the values of the following.

(a) (fg) '(5) =

(b) (f/g) '(5) = -31

Answer 1

Using the Product Rule, (fg)'(5) = f'(5)g(5) + g'(5)f(5) = (7)(-1) + (8)(3) = 17

Answer 2

(f * g)' = f' * g + f * g'