Evaluating $\iiint_E(x^2+y^2+z^2)\ dx\ dy\ dz$ where $E$ is an ellipsoid I have a practice exercise involving triple integrals and I'm not really sure where to start.

Evaluate the triple integral
  $$\iiint_E(x^2+y^2+z^2)\ dx\ dy\ dz$$
  where $E$ is defined by $(\frac xa)^2+(\frac yb)^2+(\frac zc)^2\le1$ with $a,b,c\in\Bbb R^+$.


HINT:First substitute $x=aX , y=bY , z=cZ$. Now use spherical coordinates
