Помогите (a-3)(a+2)-(a-1)^3

Question

Помогите (a-3)(a+2)-(a-1)^3

Answer 1

(a-3)(a+2)-(a-1)^3= 

=a^2+2a-3a-6-(a^3-3a^2+3a-1^3)= 

=a^2+2a-3a-6-(a^3-3a^2+3a-1)=

=a^2+2a-3a-6-a^3+3a^2-3a+1= 

=4a^2-4a-5-a^3