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!