Answer
$(x+6)^2$.
Work Step by Step
The given polynomial is
$=x^2+12x+36$
Write the the polynomial as $a^22ab+b^2$.
$=x^2+2(x)(6)+6^2$
Use perfect square trinomial pattern
$a^2+2ab+b^2=(a+b)^2$
We have $a=x$ and $b=6$.
$=(x+6)^2$
Hence, the factor of the given polynomial is $(x+6)^2$.
