PLEASEEE HELP ANSWER THESE TWO WITH REASONABLE ANSWERS AND I WILL GIVE BRANLIEST!

Can someone explain to me how to do

40 points. given: two congruent angles ∠c and ∠r are supplementary. prove: ∠r and ∠c are both right angles. it doesn't have to be exactly 10 rows.statements reasons1. 1. 2. 2. 3. 3. 4. 4. 5. 5. 6. 6. 7. 7. 8. 8. 9. 9. 10. 10.

Interpret the following expression (5y^2-7)^3/(2y)^2