Answer: A. f(g(x)) =x and g(f(x))=x and f and g are inverses.
Explanation:
A function g is the inverse of function f if
f(g(x)) = g(f(x))=x
Given: f(x)= x+4 , g(x) = x-4
f(g(x)) = f(x+4) = (x-4)+4
= x-4+4 = x
i.e. f(g(x)) =x
g(f(x))= g(x-4) = (x-4)+4 =x
i.e. g(f(x))=x
Hence, f(g(x)) =x and g(f(x))=x and f and g are inverses.