Answer
$x=\left\{ 3,6 \right\}$
Work Step by Step
The factored form of the given equation, $
x^2+18=9x
,$ is
\begin{align*}
x^2-9x+18&=0
\\
(x-3)(x-6)&=0
.\end{align*}
Equating each factor to zero (Zero Product Property), the solutions of the equation above are
\begin{align*}
x-3&=0
\\\\\text{ OR}\\\\
x-6&=0
.\end{align*}
Solving each equation above results to
\begin{align*}
x-3&=0
\\
x&=3
\\\\\text{ OR}\\\\
x-6&=0
\\
x&=6
.\end{align*}
Hence, the solutions are $
x=\left\{ 3,6 \right\}
.$