Step-by-Step Solution:
f (f) - g(x) = x 1/2 - x- (2x^3 - x 1/2 - x)
f (f) - g(x) = x 1/2 - x- 2x^3 + x 1/2 + x
f (f) - g(x) = 2x 1/2 - 2x^3