Math Help - Please solve this equation

Hi guys,
I have a problem in solving this equation.
I can not do this simple equation to solve.
The equation is given below.

But I do not know how to solve it?
Can you help me?!
if $\frac{a-3}{4}=2$
$4*\frac{a-3}{4}=4*2$
that is $a-3=8$
$a-3+3=8+3$
$a=11$