When we look at the coefficients, there is a common factor of 4 with 16 and 4. The p's are also common factors, and we can take out a common factor of x^3. We can combine these common factors and take them out of the equation at the same time.
describes a circle of radius 2 centered at (0,2). A revolution of this region about the y-axis would give you a sphere of radius 2, so the volume would be .