Complete the square x² - 2x

We do not have an equals sign so lets say it is equal to y

y=x^2-2x

take 1/2 of b and square it

-2/2=-1, (-1) ^2=1

add - 1 and 1

y=x^2-2x+1-1

copmlete square

y = (x-1) ^2-1

the copmleted squaer form is

(x-1) ^2-1