Question

已知a^3+b^3=27,ab-ab=-6,求代数式（b^3-a^3）+（ab-3ab）-2（b^3-ab）的值.

Answer 1

(b^3-a^3)+(a^2b-3ab^2)-2(b^3-ab^2) =b^3-a^3+a^2b-3ab^2-2b^3+2ab^2 =-a^3-b^3+a^2b-ab^2 =-(a^3+b^3)+(a^2b-ab^2) =-27+(-6) =-33