We we are asked to solve this kind of problem we are asked to find the value of the value (x in this case). So the first thing we want to do isolate x by subtracting 5/12 from both sides.
x+5/12-5/12=5/8-5/12
Simplify
x=5/8-5/12
Reduce
x=3/3(5/8)-2/2(5/12)
x=15/24-10/24
x=5/24