A cura di: Alfredo Bochicchio

$a(x^2+2y+z^3)+2b(x^2+2y+z^3)-c(x^2+2y+z^3)$
$(X^2+2y+z^3)(+2b+a-c)$
$(a+b)^3-2(a+b)^5$
$(a+b)^3[1-2(a+b)^2]$