The equation of a circle with center C(h,k) and radius r is given as:
[tex](x-h)^2+(y-k)^2=r^2[/tex]In this case we have the equation:
[tex](x-7)^2+(y+4)^2=r^2[/tex]Comparing with the equation of the circle we have:
[tex]\begin{gathered} h=7 \\ k=-4 \\ r^2=74 \end{gathered}[/tex]Therefore, the center of the circle is (7,-4) and the radius is √74