How do you solve 12h-7=7h+18 as a 2-step equation

Step one: 
12h-7=7h+18
12h-7h-7+7=7h-7h+18+7     Additive inverse 
5h=25

Step two:
5h=25
5/5h=25/5                             Multiplicative inverse
h=5

12h-7=7h+18
-7h     -7h

5h-7=18
    +7 +7

5h=25

5h/5= 25/5

h=5   

1. Subtract the 7h from both sides to cancel out the 7h (7h-7 and 12h-7)
equation becomes 5h-7=18

2. Add the 7 on the left side of the equation to both sides to cancel out the -7 (-7+7 and 18+7)
equation becomes 5h=25

3. Divide by 5 to cancel out the 5h (5h/5 and 25/5)
equation becomes h=5 solving for h and giving you your final answer

If gravity is one third on mars then weight also one third on mars