Find the volumes of the solids generated by revolving the region between y = 4x and y = x22 about a) the x-axis and b) the y-axis. The volume of the solid generated by revolving the region between y = 4x and y = x22 about the x-axis is cubic units. (Round to the nearest tenth.) The volume of the solid generated by revolving the region between y = 4x and y = x22 about the y-axis is cubic units. (Round to the nearest tenth.)