Joey has to solve the system of equation using substitution he has completed the work shown what should be his next step

Find the volume of the described solid.the solid lies between planes perpendicular to the x-axis at x = 0 and x=7. the cross sectionsperpendicular to the x-axis between these planes are squares whose bases run from the parabolay=-31x to the parabola y = 30/x.a) 441b) 147c) 864d) 882

Im literally having a mental breakdown

What are two numbers that add up to -9 and multiply to -10 best answer gets branliest and 100 extra points