It depends. You'd need to give some example, but generally the idea is to put all variables on one side and everything else on the other side.
Answer:
8 dollars
Step-by-step explanation:
We can write a ratio to solve
15 stickers 12 stickers
------------------ = ----------------------
10 dollars x dollars
Using cross products
15 *x = 12 * 10
15x = 120
Divide each side by 15
15x/15 = 120/15
x =8
8 dollars
as you should know, to get the inverse of any expression, we start off by doing a quick switcheroo on the variables and then solve for "y".

Answer:PQ
Step-by-step explanation: __
Line up the two: BCDE
OPQR
If they are the same which is equal to the same thing?
*hint* the two middle letters.