galactus clearly meant z= -x+ 5.z varies from z=1 to x = -x+5
y varies from \(\displaystyle x^{2}+y^{2}=9\Rightarrow y=\pm\sqrt{9-x^{2}}\)
and x varies from -3 to 3.
\(\displaystyle \displaystyle \int_{-3}^{3}\int_{-\sqrt{9-x^{2}}}^{\sqrt{9-x^{2}}}\int_{1}^{-x+5} dzdydx\)