Please help ASAP please

What is the average rate of change for this function for the interval from x=2 to x=4 ?

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

If the sales price of a dvd is $20 and the markup is 34%, what is the cost of the dvd?