Answer
The answer is $n^{3}$ + $15n^{2}$ + $56n$.
Work Step by Step
When you insert V=lwh, you get V= (n)(n+7)(n+8). When you simplify (n+7)(n+8), you get $n^{2}$ + $15n$ + $56$. Lastly, you multiply the whole polynomial by n, which results in the answer $n^{3}$ + $15n^{2}$ + $56n$.
