Question

If f(x) = x2 − 2x + 9 and g(x) = 8 − x, what is (f o g)(−4)?

Select one of the options below as your answer:




A.
111





B.
144





C.
120





D.
129

Answer 1

Evaluate g(x) at -4, then input that into f(x)

Answer 2

g(-4) = 12
Now write f(12).
(12)^2-2(12) + 9 = 129

Answer 3

It's called composition. You could also write it as:
f(g(x)) = (8-x)^2 -2(8-x) + 9
Now sub in -4 for x. f(g(x)) = 129