Respuesta :

It is centered at (h,k) --> (0,0) and has a radius 9

The equation of the circle is

           [tex](x-h)^{2} +(y-k)^{2} =r^{2} \\(x-0)^{2} +(y-0)^{2} =r^{2}\\x^{2} +y^{2} = 9^{2}[/tex]

Hope that helps!