substitution in equations

This is a newbie question I'm sure, but I really can't find help anywhere on the net about the rules of substitution (I guess I should have just listened up in gradeschool).
I wanted to find the raw score from a z score: z = x-m/SD and I found the answer to be x = (z)(SD)+m, but how is this done? Where did the fraction go? If anyone could just refer me to a webpage they know of explaining me these rules I would also be very happy for that.


New Member
z = (x-m)/SD

[multiply both sides with SD]

z*sd = x-m

[Add m on both sides]

z*sd + m = z

This is extremely basic, so I think it would be a good idea to take a look into your old schoolbooks or something.