已知x-y=1,xy=2,求x³y-2x²y²+xy³的值

已知x-y=1,xy=2,求x³y-2x²y²+xy³的值
已知x-y=1,xy=2,求x³y-2x²y²+xy³的值

已知x-y=1,xy=2,求x³y-2x²y²+xy³的值
x³y-2x²y²+xy³
=xy(x²-2xy+y²)
=xy(x-y)²
=2X1
=2

假设X=2，Y=1
则 x³y-2x²y²+xy³=2
过程省略。。。。。。O(∩_∩)O