Answer:
[tex]from \: general \: equation \\ {x}^{2} + {y}^{2} + 2gx + 2fy + c = 0 \\ at \: the \: origin \: \: g = 0 \: and \: f = 0 \\since \: c = {g}^{2} + {f}^{2} + {r}^{2} \\ whe re \: r \: is \: radius \\ therefore \: c = {3}^{2} = 9 \\ = > {x}^{2} + {y}^{2} + 9 = 0[/tex]
