4=18-3w
18 - 3w=4
+18 +18
-3w=22
7 1/3
no
first of all your answer, if that number is supposed to be the answer, is incorrect
secondly, I do not like the way you present your answer
proper way:
4 = 18 - 3w
3w = 18-4
3w = 14
w = 14/3 or 4 2/3