Answer
$V$ = $6\pi$
Work Step by Step
$V$ = $\int\int[(6-x^2-y^2)-(2x^2+2y^2)]dA$
$V$ = $\int\int(6-3r^2)rdrdθ$
$V$ = $\int_0^{2\pi}\int_0^{\sqrt 2}(6r-3r^3)drdθ$
$V$ = $\int_0^{2\pi}[3r^2-\frac{3}{4}r^4]_0^{\sqrt 2}dθ$
$V$ = $\int_0^{2\pi}[(6-3)-0]dθ$
$V$ = $\int_0^{2\pi}3dθ$
$V$ = $3[θ]_0^{2\pi}$
$V$ = $6\pi$