f(x) = x + 2 g(x) = x – 4(f g)(x) =

Here, (fg)(x) means f(x) times g(x). Substitute the given functions: (x + 2)(x − 4) = x² − 4x + 2x − 8 = x² − 2x − 8. So the correct choice is C, x² − 2x − 8.

AI-written and checked against the verified answer.