Find center and radius...?

center is (8,17)

radius is sqrt(13)

general equation for a cicle is

(x - h)² + (y - k)² = r²

where the center is (h, k) and r is the radius.

Nope....

Remember the basic formula?

x^2 + y^2 = r^2

Therefore, the center is (8, 17), but your radius is SQRT(13)

(x-a)² + (y-b)² = r² is a circle radius r common at (a, b). x²+y²+4x+6y-3 = x²+4x+4 + y²+6y+9 - (4+9+3) so (x-(-2))² + (y-(-3))² = 4² this would nicely be a circle of radius = 4, concentrated on (-2, -3)

You have the right centre, but remember

(x - x1)^2 + (y - y1)^2 = r^2

So should you be squaring 13, or doing something else?

(x-8)^2+(y-17)^2=13

(x^2-8^2)+(y^2-17^2)=13

(x^2+64)+(y^2+289)=13

x^2+y^2+353=13

x^2+y^2=-340

That's the best i can do. I believe this is right and you can try to solve it from here.

Centre (8,17)

r² = 13

r = √13

center is correct ..

radius is root(13)

I am pretty sure you are right but I'm not positive.

What formulas are you using?

yeah thats right