A cura di: Alfredo Bochicchio

$4a^3c+36ab^2c+24a^2bc-4ac^5$
$4ac(a^2+9b^2+6ab-c^4)$
$4ac[(a+3b)^2-(c^2)^2]$
$4ac[(a+3b+c^2)(a+3b-c^2)]$