Answer
$x^2+2x-6$
Work Step by Step
Given \begin{equation}
\begin{aligned}
\left(x^3+5x^2-18\right) \div(x+3).
\end{aligned}
\end{equation} Use synthetic division. \begin{equation}
\begin{array}{r|rrrr}
-3&1 & 5 & 0 &-18 \\
& & -3 & -6& 18 \\
\hline &1 & 2 & -6 & 0
\end{array}
\end{equation} The solution is \begin{equation}
\begin{aligned}
\frac{x^3+5x^2-18}{x+3}=x^2+2x-6.
\end{aligned}
\end{equation}
