solve:

Question

x -8 = 4
+ 8 +8
x = 12

my answer is x = 12

solve:
80 = 10x
-- ---
10 10

8 = x

my answer is x =8

solve:
3x= -12
-- ---
3 3

x = -4

my answer is x = -4

Solve:
12 -3x = 9
-12 -12
-3x = -3
--- ---
-3 -3

x = 1

my answer is x = 1

ok on all of them.