Answer
$(3x-1)(3x+1)(9x^2+1)$
Work Step by Step
The given binomial can be written as:
$=(9x^2)^2-1^2$
The binomial is a difference of two squares.
RECALL:
$a^2-b^2=(a-b)(a+b)$
Factor the difference of two square using the formula above with $a=9x^2$ and $b=1$ to obtain:
$=(9x^2-1)(9x^2+1)
\\=[(3x)^2-1^2)](9x^2+1)$
The first factor is a difference of two squares. Factor using the formula above with $a=3x$ and $b=1$ to obtain:
$=(3x-1)(3x+1)(9x^2+1)$
