已知x-y=-1,xy=3,求x^3y-2x^2y^2+xy^3
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![已知x-y=-1,xy=3,求x^3y-2x^2y^2+xy^3](/uploads/image/z/1255709-29-9.jpg?t=%E5%B7%B2%E7%9F%A5x-y%3D-1%2Cxy%3D3%2C%E6%B1%82x%5E3y-2x%5E2y%5E2%2Bxy%5E3)
已知x-y=-1,xy=3,求x^3y-2x^2y^2+xy^3
已知x-y=-1,xy=3,求x^3y-2x^2y^2+xy^3
已知x-y=-1,xy=3,求x^3y-2x^2y^2+xy^3
x^3y-2x^2y^2+xy^3=xy(3x^2-4xy+y^2)=xy(3x-y)(x-y)
x-y=-1,xy=3 y(y-1)=3
x³y-2x²y²+xy³
=xy(x²-2xy+y²)
=xy(x-y)²
=3•(-1)²
=3