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