To solve for u, you just have to isolate it. Let's take it step by step:
1. Add 5 to both sides to get rid of it on one side:
[tex]-5+5+3u=-14+5[/tex]
[tex]3u = -9[/tex]
Divide by 3 to get rid of it:
[tex] \frac{3u}{3} = \frac{-9}{3} [/tex]
[tex]u = -3[/tex]
So, we have found the value of u, it is: u = -3
