Which pair of functions are inverses?
A.f(x) = 2x + 1, g(x) = 2x - 1
B. f(x)=3x+2. g(x)= 1/3x-2/3
C. f(x) = 4x, g(x) = -4x
D. f(x)= x+1/5, g(x)= x+5