Can someone please help me with this question?

Find the solution of this system of equation -7x+y=-20 9x-3y=36

Reinel saves 30% of every pay check. his paycheck last week was 560$. how much did reniel save last week?

Astudent draws two parabolas both parabolas cross the x axis at (-4,0) and (6,0) the y intercept of the first parabolas is (0,-12). the y intercept of the second parabola is (0,-24) what is the positive difference between the a values for the two functions that describe the parabolas