f(x)= x-2/x+2,g(x)=x+2 (fog)-1(x) = .... mohon dibantu

f(x)= x-2/x+2 dan g(x)=x+2 

(fog)(x) = (fo(x+2)
             =(x+2)-2/(x+2)+2
          y   =  x/ x+4
(fog)^-1 = x/ x+4
y^-1 = -4x/x = -4