Answer
$(x^3+5)(2x^3+3)$.
Work Step by Step
The given expression is
$=2x^6+13x^3+15$
We can write
$=2(x^3)^2+13x^3+15$
Substitute $x^3=u$.
$=2(u)^2+13u+15$
Simplify.
$=2u^2+13u+15$
Rewrite $13u$ as $10u+3u$.
$=2u^2+10u+3u+15$
Factor.
$=2u(u+5)+3(u+5)$
$=(u+5)(2u+3)$.
Substitute back $u=x^3$.
$=(x^3+5)(2x^3+3)$.
