I don't know how to do the problem. can someone please show work and explain how to do the problem?

Using rectangles whose height is given by the value of the function at the midpoint of the rectangle's base (the midpoint rule), estimate the area under the graph ofthe following function, using two and then four rectangles. y=64x2 between x= B and x=a For two rectangles, area at E (Type an integer or a decimal) For four rectangles' area a: :| (Type an integer or a decimal.)