The equation of the circle centered at (h,k) with radius r is:
[tex](x-h)^2+(y-k)^2=r^2[/tex]In this case, the center is (5, -3) and the radius is 16, then the equation is:
[tex]\begin{gathered} (x-5)^2+(y-(-3))^2=16^2 \\ (x-5)^2+(y+3)^2=256 \end{gathered}[/tex]