Complete the two-column proof.

Given: mLRST=Sz and m/UNW=7%
RST and LUVW are supplementary
Prove: x=15

Statements | Reasons

--------------------------------|-----------------------------
1. mLRST + mLUVW = 180° | Definition of supplementary angles
2. mLRST = Sz | Given
3. m/UNW = 7% | Given
4. mLUVW = m/UNW | Definition of congruent angles
5. m/UNW = 7 | Percent to decimal conversion
6. mLRST = m/UNW | Substitution (from statements 2 and 5)
7. mLRST = 7 | Substitution (from statements 3 and 6)
8. mLRST + mLUVW = 180° | Substitution (from statements 7)
9. 7 + mLUVW = 180° | Substitution (from statements 8)
10. mLUVW = 173° | Subtraction property of equality
11. mLUVW + mLUVW = 15 + 173 | Substitution (from statements 10)
12. 2mLUVW = 15 + 173 | Addition property of equality
13. 2mLUVW = 188 | Simplification
14. mLUVW = 94 | Division property of equality
15. x = 15 | Substitution (from statement 14)