Answer
$n=-3$
Work Step by Step
$$\begin{align*}
-2n+3-3&=9-3 &\text{Subtract 3 from each side.}\\
-2n&=6 &\text{Simplify.}\\
\frac{-2n}{-2}&=\frac{6}{-2} &\text{Divide -2 to both sides.}\\
n&=-3 &\text{Simplify.}
\end{align*}$$
Check the answer by substituting $-3$ to the variable in the given equation.
$$\begin{align*}
-2n+3&=9\\
-2(-3)+3&\stackrel{?}{=}9\\
6+3&\stackrel{?}{=}9\\
9&\stackrel{\checkmark}{=}9
\end{align*}$$
