(a-3)(a-2)-(a-1)^3= a^2 -3a-2a -a^3 +3a^2 -3a +1 =-a^3 +4a^2 -8a +1
a^2-2a-3a+6-a^3-3a^2*b-3a*b^2-b^3=-a^3-3a^2*b-3a*b^2-b^3-a
(a-3)(a-2)-(a-1)^3= a^2 -3a-2a -a^3 +3a^2 -3a +1 =-a^3 +4a^2 -8a +1
a^2-2a-3a+6-a^3-3a^2*b-3a*b^2-b^3=-a^3-3a^2*b-3a*b^2-b^3-a