# circles

• January 24th 2009, 12:41 PM
Yup318
circles
I need some help with a problem.If someone could explain on how to solve

Find the center and radius of the circle

x2 + y2 - 2x =0

I already have the answers (1,0) r=1

I'm just confused on how to go about solving. I know I use the formula

(x-h)2 + (y-k) = r2

I'm just confused on the complete the square part, any help is appreciated!
• January 24th 2009, 12:43 PM
vincisonfire
You must complete the square for x and y $x^2 + y^2 - 2x = x^2 - 2x +1 - + y^2 = (x-1)^2 + y^2 -1 = 0$
$(x-1)^2 + (y-0)^2 = 1$