it is very simple actually. if you look carefully you should realise that the answer is -1. because if you replace x by -1 every paranthesis becomes 0(zero) so it satisfies the equation. but if you need the proof...

first lets open the eq.
(4x+4)/2 -(15x+15)/2 + (5x+5)/2 = 0

multiply everything by 2 and get rid of the paranthesis
4x+4-15x-15+5x+5=0

and just solve the eq.
-6x = 6
x= -1

that is it...
hope it helps.

murat