Question

Find the center and radius of x2^ + y^2 + 2x - 10y + 10 = 0
a.center (1, - 5); r = 16
b.center (1, -5); r = 4
c.center (-1, 5); r = 16
d.center (-1, 5); r= 4

Answer 1

The arrangement that makes it easy to determine such things is this:
(x - h)^2 + (y - k)^2 = r^2
where (h,k) is the center and r is the radius.

Can you rearrange/manipulate your equation to look like this?

Answer 2

the correct answer is b