How do you verify this problem?

Small kingdoms on the iberian peninsula fought to take land back from the moors during which event? the hundred years’ war the wars of the roses the reconquista the great schism

Answers; a) 135 degree’s b) 30 degree’s c) 180 or 0 degree’s d) 90 degree’s

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