Answer:
(f•g)(x) = 5x^3 + 15x^2 + 15x + 5
Explanation:
If f(x) = 5x^3 and g(x)= x+1 find (f•g)(x)
(f•g)(x) = (f(g(x))
So
(f(g(x)) = 5(x+1)^3
= 5(x+1)(x+1)^2
= (5x + 5)(x^2 + 2x + 1)
= 5x^3 + 10x^2 + 5x + 5x^2 + 10x + 5
= 5x^3 + 15x^2 + 15x + 5
So
(f•g)(x) = 5x^3 + 15x^2 + 15x + 5