Answer
$(5x+1)(x^2+1)$
Work Step by Step
Regroup to obtain:
$=(5x^3+x^2)+(5x+1)$
Factor out $x^2$ in the first group to obtain:
$=x^2(5x+1)+(5x+1)$
Factor out the greatest common factor $(5x+1)$ to obtain:
$=(5x+1)(x^2+1)$