Answer
$ (x-2)^2$
Work Step by Step
The given polynomial is
$\Rightarrow x^2-4x+4$
Write the the polynomial as $a^2-2ab+b^2$.
$\Rightarrow x^2-2(x)(2)+2^2$.
Use perfect square trinomial pattern $a^2-2ab+b^2=(a-b)^2$.
We have $a=x$ and $b=2$.
$\Rightarrow (x-2)^2$.
Hence, the factor of the polynomial is $ (x-2)^2$.
