Question

Find the center and radius of x squared plus y squared plus 2 x minus 10 y plus 10 equals 0.

Answer 1

Center is (-1, 5) and radius = 4.

Explanation:

x^2 + y^2 + 2x - 10y + 10 = 0

This is a circle. The first thing is to complete the square:

x^2 + 2x + y^2 - 10y = -10

(x + 1)^2 - 1 + (y - 5)^2 - 25 = -10

(x + 1)^2 + (y - 5)^2 = 16 Comparing this to the standard equation:

(x - h)^2 + ( y - k)^2 = r^2

- we see that the center (h, k) is (-1, 5) and the radius r = 4.

(x +1 )^2 + (y - 5)^2 = -10+