The key is to separate it into separate integrals over the distinct regions of the plane where (and the integrand thus equals ), and the regions where (and the integrand equals ). The curves dividing the plane into these regions are the solutions to , which gives , , and . These two lines and one parabola divide the plane into six regions; you will have the sum of the integrals of over three of these regions and the integrals of over the other three regions.

--Kevin C.