Answer
$(n-3)(n+6)$
Work Step by Step
The following pairs of numbers give a product of $
-18
:$
\begin{array}{l}\require{cancel}
\{ 1,-18 \}
\text{ }
\{ -1,18 \}
\text{ }
\{ 2,-9 \}
\text{ }
\{ -2,9 \}
\text{ }
\{ 3,-6 \}
\text{ }
\{ -3,6 \}
.\end{array}
Of these pairs, the one which gives a sum of $
3
$ is the pair $\{
-3,6
\}.$
Hence, the factored form of the given expression, $
n^2+3n-18
$ is
\begin{array}{l}\require{cancel}
(n-3)(n+6)
.\end{array}
