8x-8=72
+8 +8
8x=80
8x/8 80/8
X=10
1st step do the opposite of subtracting which is adding so add 8 on each side like shown above .
2nd step after adding and canceling you bring down 8x=80
3rd step you need to get x by itself so divide 8 in each side shown above
4th step the answer is X=10