Answer
$(6x+3)(6x-3)$
Work Step by Step
$36x^2-9$
To factor the difference of two squares, we can refer to the general form that any difference of two squares can be written as, that is
$(x^2-a^2)=(x+a)(x-a).$
Therefore, the answer can be written as:
$(6x+3)(6x-3)$
