#### Answer

$\color{blue}{(x^6+9)(4-y)}$

#### Work Step by Step

Regroup:
$=(4x^6+36)+(-x^6y-9y)$
Factor out $4$ in the first and $-y$ in the second group to obtain:
$=4(x^6+9)+(-y)(x^6+9)$
Factor out $x^6+9$ to obtain:
$=(x^6+9)[4+(-y)]
\\=\color{blue}{(x^6+9)(4-y)}$