A function f:R→Rf: \mathbb{R} \to \mathbb{R}f:R→R is defined by f(x)=x2−2xf(x) = x^2 - 2xf(x)=x2−2x. Find the set of all xxx such that f(f(x))=xf(f(x)) = xf(f(x))=x.
{0,1,2,3}\{0, 1, 2, 3\}{0,1,2,3}
{1,1±2}\{1, 1 \pm \sqrt{2}\}{1,1±2}
{0,2}\{0, 2\}{0,2}
{1,1±i}\{1, 1 \pm i\}{1,1±i}