x^2 + y^2 + 2x – 10y + 10 = 0
x^2 + 2x + y^2 - 10y = 0
We must complete the square in x and y.
(x^2 + 2x + 1) + (y^2 -10y + 25) = 4 + 25
(x + 1)^2 + (y - 5)^2 = 29
The radius r is found solving r^2 = 29 for y.
(x + 1)^2 + (y - 5)^2 = sqrt{29}
See picture for the center and radius.
