1. a) (f o g)(x) = f (g(x)) so to find an expression for (f o g)(x) you replace every occurence of x in the expression for f(x) by 2x - x2.
(f o g)(x) = f (g(x)) = f (2x - x2) = (2x - x2)3.
(g o f)(x) = g( f (x)) so to find an expression for (g o f)(x) you replace every occurence of x in the expression for g(x) by x3.
(g o f)(x) = g( f (x)) = g( x3) = 2x3 - (x3)2 = 2x3 - x6 .
b) No. (f o g)(x) is not equal to (g o f)(x).