Answer
See below
Work Step by Step
This function is in the form $a(x-p)(x-q)$. We know that the axis of symmetry is $\frac{p+q}{2}$.
We need the axis of symmetry to be $x=3$.
Then, $\frac{p+q}{2}=3\\\rightarrow p+q=6\\
\rightarrow p=6-q$
Assume $q=2 \rightarrow p=6-2=4$
Obtain the function: $y=(x-4)(x-2)$
$q=4 \rightarrow p=6-4=2$
Obtain the function: $y=(x-2)(x-4)$