Answer:
(0,0) and r=3
Step-by-step explanation:
To find the radius and center rewrite the equation in vertex form [tex](x-h)^2+(y-k)^2 = r^2[/tex].
First move x and y to the other side so they have positive signs. Then move 9 across to the other side too.
[tex]-9 = -y^2 -x^2\\x^2 + y^2 -9 = 0\\x^2 + y^2 = 9[/tex]
Here you can see there is no h or k meaning h=0 and k=0. The radius is the square root of 9 which is 3.
