Answer:
D
Step-by-step explanation:
f(g(x)) = x when the two functions are inverses
A. f(g(x)) = 2/((x+6)/2) - 6 = (4/(x+6)) - 6 = (4 - 6x - 36)/(x+6) = -(6x+32)/(x+6), wrong
B. f(g(x)) = [tex]\frac{\sqrt[3]{5x^{3} } }{5}[/tex] = x[tex]\frac{\sqrt[3]{5} }{5}[/tex], wrong
C. f(g(x)) = (3x-4)/3 + 4 = x + (8/3), wrong
D. f(g(x)) = 2((x+9)/2) - 9 = x
