Lf P=3y2 + 2xy-2x, Q = 2x2 + 4xy-y2 and R=5x2-3xy then
show that P+(Q+R) = (P+Q) + R.​

Find the volume v of the solid obtained by rotating the region bounded by the given curves about the specified line. y = x â’ 1 , y = 0, x = 5; about the x-axis v = sketch the region. sketch the solid, and a typical disk or washer.