已知:x+y=5,x²+y² =11,求代数式x³y-2x²y²+xy³的值
问题描述:
已知:x+y=5,x²+y² =11,求代数式x³y-2x²y²+xy³的值
答
x³y-2x²y²+xy³
=xy(x²-2xy+y²)
=xy(x-y)²
=xy[(x+y)²-4xy]
=5x(11²-4x5)
=5x101
=505