8x-8=-72 how would i find the answer

-8 + -8 + -8 + -8 + -8 + -8 +-8 +-8 = -72
that's one way to solve it. 

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

On monday,mrs.wise bought 3 lbs of apples at $4per lb= 4*3=$12on tuesday ,20%off and she buy 5 lbs of apples = $4-20%=3.20*5lb=$16example: other wise when she buy 5lbs on monday she have to spend 4*5=20