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Can someone me and do the problem plz so i can understand it more better

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

The measure of one angle of an octagon is two times smaller that of the other seven angles. what is the measure of each angle?