operations on function

Perform the following:
Find (f g)(x), ) (x) and (4) (x); if

1. f(x) = x² and g(x) = 4x
2. f(x) = 2x2y3 and g(x) =6xyz 4x
3. f(x) == and g(x) = x² 2
4. f(x) = 2x² + 4x + 2 and g(x) = 2x + 2
5. g(x)=x²-9 and f(x) = x + 3​