I need help! Question is in the picture!

Solve the given system of equations. 2y= -x+9 , 3x-6= -15

To solve the system of equations below, pedro isolated the variable y in the first equation and then substituted it into the second equation. what was the resulting equation? { 5y=10x {x^2+y^2=36

List the sides of δrst in ascending order (shortest to longest) if: m∠r =x+28°, m∠s = 2x+16°, and m∠t = x+12