Answer
$c=\{ 2,4 \}$
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, $
(c-2)(c-4)=0
$, is
\begin{array}{}
c-2=0
\\
c=0+2
\\
c=2
,\\\\\text{OR}\\\\
c-4=0
\\
c=0+4
\\
c=4
.\end{array}
Hence, $
c=\{ 2,4 \}
$.