What we have to do first is draw the cartesian plane.
We know that the center of the circle is located in x=3 the line in green and that it passes through (6,5) point A.
A circle is represented by the equation:
[tex]\begin{gathered} (x-h)^2+(y-k)=r^2 \\ r^2=(\sqrt[]{13})^2=13 \end{gathered}[/tex]
The equation of this circle is, having the point A (6,5)
[tex](6-h)^2+(5-k)^2=13[/tex]Being (h,k) the center of the circle.