f(x) = x + 2 g(x) = x – 4(f g)(x) =

Treat (fg)(x) as the product f(x)g(x). Substitute the given expressions and multiply: (x + 2)(x − 4) = x² − 4x + 2x − 8 = x² − 2x − 8, which is choice C.

AI-written and checked against the verified answer.