1) 18h = 252
You divide each side by 18, so you can get "h" alone on a side, and its value on the other side of the equation.
(18h)/18 = 252/18
h = 14 (Answer C)
2) 31d = 186.
Same Thing, you divide each side by 31, so you can get "d" alone on a side, and its value on the other side of the equation.
(31d)/31 = 186/31
d= 6 (Answer B)
3) 55c = 385
Again, same thing, You divide each side by 55, so you can get "c" alone on a side, and its value on the other side of the equation.
(55c)/55 = 385/55
c = 7 (Answer B)
4) 50w = 1050
You divide each side by 50, so you can get "w" alone on a side, and its value on the other side of the equation.
(50w)/50 = 1050/50
w=21 (Answer A)
As you can notice, they all follow the same steps: dividing by the coefficient of the variable both sides, so you can the variable alone on the first side of the equation, and its value on the second side.
Hope this Helps! :)