Find the volume of the solid.

I'm stuck on this problem. The answer is probably obvious, but I second guess myself a lot.

Find the volume of the solid below z=sqrt((x-y)(x+4y)), above the parallelogram in the x-y plane with vertices (0,0)(1,1)(5,0)(4,-1).

I have drawn myself a graph to visualize.

Since I havent figured out the way to input stuff on this forum yet, bare with me.

My setup so far is:

triple integral : integral from 0 to 5, integral from -1 to 1, integral from 0 to Z eqn above dzdydx.

The hint given with the problem is change of variables. I've started working it, but since I cant recall what change of variables Im looking to use, my work doesnt seem right so far.