(a-3)(a2+3a-9)=

题目

(a-3)(a2+3a-9)=
(a-3)(a^2+3a-9)=?
(x-1)(x^2-x+1)=?

答案

(a-3)(a^2+3a-9)
=a^3+3a^2-9a-3a^2-9a+27
=a^3-18a+27
(x-1)(x^2-x+1)
=x^3-x^2+x-x^2+x-1
=x^3-2x^2+2x-1