Answer
$x=0$ and $x=-6$
Work Step by Step
Square the binomial to obtain:
$$x^2+6x+9=9$$
Subtract $9$ from each side:
$$x^2+6x=0$$
Factor the binomial:
$$x(x+6)=0$$
Use the Zero-Product Property by equating each factor with a variable to zero, then solve each equation to obtain:
\begin{align*}
x&=0 &\text{or}& &x+6=0\\
x&=0 &\text{or}& &x=-6
\end{align*}
Thus, the solutions are $x=0$ and $x=-6$.