Question

若a-b=-1,ab=3,求a^3b-2a^2b^2+ab^3的值

利用初一知识解答．谢谢！

Answer 1

a-b=-1,ab=3,
a^3b-2a^2b^2+ab^3
=ab(a^2-2ab+b^2)
=ab(a-b)^2
=3*(-1)^2
=3

Answer 2

a^3b-2a^2b^2+ab^3
=ab(a^2-2ab+b^2)
=ab(a-b)^2
=3*(-1)^2
=3*1
=3