Answer
$(x^{3}-3)(x^{3}+2)$
Work Step by Step
Substituting $x^{3}=t$, the trinomial becomes quadratic,
$t^{3}-t-6=$
... Searching for two factors of $-6$ whose sum is $-1,$
we find$\qquad-3$ and $+2$
$=(t-3)(t+2)$
... bring back x
= $(x^{3}-3)(x^{3}+2)$