Question 35505
Let f(x) = 2x + 1 and g(x) = x^2 - 4 

(fg)(x) has two meanings whether it is component wise multiplication or composition
if it is multiplication then (fg)(x) = f(x)*g(x) and if it is composition then (fg)(x) = f(g(x)). There are condition underwhich each of the above is valid

I am assuming it is multiplication here
(fg)(x) = f(x)*g(x) = (2x + 1)*(x^2 - 4) = 2x^3 + x^2 -8x -4


(f-g)(x) = f(x) - g(x) = 2x + 1 - (x^2 - 4) =  2x + 1 - x^2 + 4= -x^2 + 2x + 5