Hopes this helps:
Answer: u = 4
1. Expand.
9u - 6 = 6u + 6
2. Add 6 to both sides.
9u = 6u + 6 + 6
3. Simplify 6u + 6 + 6 to 6u + 12.
9u = 6u + 12
4. Subtract 6u from both sides.
9u - 6u = 12
5. Simplify 9u - 6u to 3u.
3u = 12
6. Divide both sides by 3.
u = 12/3
7. Simplify 12/3 to 4.
u = 4