Question 328355
To solve this problem, you want to get u by itself on one side of the problem.  So first, you want to subtract 7 from each side of the problem so the 7 on the right disappears:
-11 = 7 + 3u
-11 - 7 = 7 + 3u - 7
-18 = 3u
Now divide each side by 3 to get u by itself:
-18/3 = 3u/3
-6 = 1u
-6 = u
So your answer is u = -6.