Since you want help i wont tell you the answer..just how to solve...
(need to know) Of in math means multiply
they are giving you something to plug in to f(x) so everywhere in the equation there is an X replace with the equation and solve....in this case they are replacing f(x) with f(a+2) so take 3+x and change it to 3+a+2 and then take x-3 and make it a+2-3.
Then you have 3+a+2 divided by a+2-3
