I don't get this Please help asap!?

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

Three people are traveling and need to exchange the currency of their native country for the currency of the country they are visiting. drag each exchange to the category that shows the ratio of currencies in that exchange.

Which of the following equations is equivalent to x/3-6/x=1