Answer:
Step Reason
1. S + U = 180 Given
2. S + T = 180 Vertical angles are congruent
3. U = T Subtraction property of equality
4. R + T = 180 Supplementary angles add up to 180
5. R + U = 180 Substitution property of equality
6. S + U = R + U Transitive property of equality
7. S + U - U = R + U - U Subtraction property of equality
8. S = R Simplify
Explanation: