The formula of a volume of a rectangle prism:
[tex]V=lwh[/tex]
l - length
w - width
h - height
We have
[tex]l=n^2+2;\ w = 10,\ h=n+5[/tex]
Substitute:
[tex]V=(n^2+2)(10)(n+5)=(10n^2+20)(n+5)\\\\=(10n^2)(n)+(10n^2)(5)+(20)(n)+(20)(5)\\\\=10n^3+50n^2+20n+100[/tex]