Question 469413
{{{f o g(x) = f(x/7 - 4/7) = 7(x/7 - 4/7) + 4 = x - 4 + 4 =x}}}, and 

{{{g o f(x) = g(7x + 4) = (7x+  4)/7  - 4/7 = x + 4/7 - 4/7 = x}}}, so 

answer is a. yes.