14. The solid region bound by the cylinders $x^2 + y^2 = 3$ and $x^2 + y^2 = 9$ and the planes
z = 0 and $2x + 3y - z = -15$ has a mass density function imposed upon it given by
$\rho(x, y, z) = z(x^2 + y^2)$. What is the center of mass? Due to the amount of work
that three integrations require, you can use online calculators to perform the
integrations.