A cura di: Alfredo Bochicchio

$(-3xz^2)(-4x^2z)(1/3x)-(-2/9x^2z)(-1/4z^2)(3x^2)+(-3/2x^4z^3)$
$+12x^3z^3(1/3x)-(+18x^2z^3)(3x^2)+(-3/2x^4z^3)$
$12/3x^4z^3-(+1/6x^4z^3)+(-3/2x^4z^3)$
$4x^4z^3-1/6x^4z^3-3/2x^4z^3$
$(4-1/6-3/2)x^4z^3$
$(24-1-9)/6x^4z^3$
$7/3x^4z^3$