Answer
$(x-3)(x^2+3x+9)$
Work Step by Step
$x^3-27$
To factor the sum of difference of two cubes, let us remember
$a^3 + b^3 = (a + b)(a^2 – ab + b^2)$
and
$a^3 – b^3 = (a – b)(a^2 + ab + b^2.)$
Therefore, when we factor, we get
$(x-3)(x^2+3x+9).$