Question 153022
When functions are invereses of each other,  if you take (f(g(x)), you get x back.
Basically, the second function 'undoes' what the first one does.

{{{f(x) = 3x-4}}}
{{{f(g(x)) = 3 ((x+4)/3) - 4}}}
{{{f(g(x)) = (x+4) - 4}}}
{{{f(g(x)) = x }}}