Question

已知a^3+b^3=27,a^2-ab^2,求(a^2-3ab^2)-(b^3-ba^2)的值

Answer 1

已知a^3+b^3=27,a^2b-ab^2=-6,求(b^3-a^3)+(a^2-3ab^2)-2(b^3-ba^2)的值,是不是差了一个(a^2b-3ab^2)

原式= (b^3-a^3)+(a^2b-3ab^2)-2(b^3-ba^2)

= -(a^3+b^3) + 3 (a^2b-ab^2)

= - 27 + 18

= -9