#### Answer

$-n^{3} -3n^{2} -n -3$

#### Work Step by Step

($-n^{2}$-1)(n+3)
Use FOIL to simplify. FOIL: First (Multiply the first variables in the brackets), outside (Multiply the outer variables), Inside (Multiply the inside variables), Last (Multiply the last variables in the brackets).
By using the foil method we get
$-n^{2}(n) -n^{2}(3) -1(n) -1(3)$
We multiply the terms and simplify them
$-n^{3} -3n^{2} -n -3$