Question

Regina is trying to sketch a circle on graph paper with the equation x2+y2−2x+22y+1=0 . Calculate where she would need to graph the center and radius of the circle by completing the square.(1 point)

center= (−1,11) , radius=11

center= (−22,2) , radius=41

center= (−2,22) , radius=41

center= (1,−11) , radius=11

Answer 1

Complete the square:

x^2 − 2x = (x − 1)^2 − 1
y^2 + 22y = (y + 11)^2 − 121

So the equation becomes (x − 1)^2 + (y + 11)^2 = 121.

Thus center = (1, −11) and radius = 11. Answer: center = (1,−11), radius = 11.