Question

Let f(x) = x - 3 and g(x) = x + 11. Find f(x) · g(x).

Answer 1

Multiply both functions.
(x+11)(x-3)
X^2-3x+11x-33
Combine terms
And that's your answer

Answer 2

Unless you mean f(g(x)) then you would have to plug in the function of g into the function of f