Find the center and radius of the given circle and graph it.

Question

1. x^2+y^2+10y+21=0

Answer 1

rearrange things a bit and complete the squares:

x^2+y^2+10y+21=0
x^2 + (y^2+10y+25)+21 = 0+25
x^2 + (y+5)^2 = 4

so, center and radius are?