Answer
$x=\{ 0,9 \}$
Work Step by Step
By the Zero-Product Property, $ab=0$ implies $a=0 \text{ OR } b=0$. Hence, the solution to the given equation, $
x(x-9)=0
$, is
\begin{array}{}
x=0
,\\\\\text{OR}\\\\
x-9=0
\\
x=0+9
\\
x=9
.\end{array}
Hence, $
x=\{ 0,9 \}
$.