Answer
One possible answer:
$$x^2-2x+1=(x-1)^2.$$
Work Step by Step
Polynomials that factor into a perfect square have the form
$$x^2-2bx+b^2=(x-b)^2$$
or
$$x^2+2bx+b^2=(x+b)^2$$
As one example, we can choose $b=1$ in the first equation to obtain:
$$x^2-2x+1=(x-1)^2.$$
