Start from inside to the out side of the function;
h(5)=10/5=2
g(h)=g(2)=3*2=6
now, get the f inverse of x;
f(x)=y=x+6
x=y-6
replace x with y and y with x
y=x-6
so f^-1= x-6
so f^-1(g)=f^-1(6)=6-6=0
I am not sure only of the last value, but pretty sure of the rest.
