1. Do NOT divide both sides by $x$. This will eliminate one of your two answers.
2. Instead, move all terms to one side and set = to $0$
Factor. Solve.

$2\left(x − 6\right)^{2} = 18$
$\left(x − 6\right)^{2} = 9$
$x − 6 = ± 3$
$x = ±3 + 6$
$x = 9$ $x = 3$