,已知x+y=-3,xy=-1又2分之1,求代数式(x^3y+xy^3)/(-xy)的值

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,已知x+y=-3,xy=-1又2分之1,求代数式(x^3y+xy^3)/(-xy)的值

,已知x+y=-3,xy=-1又2分之1,求代数式(x^3y+xy^3)/(-xy)的值
,已知x+y=-3,xy=-1又2分之1,求代数式(x^3y+xy^3)/(-xy)的值

,已知x+y=-3,xy=-1又2分之1,求代数式(x^3y+xy^3)/(-xy)的值
原式=xy(x²+y²)/(-xy)=-(x²+y²)=-(x+y)²+2xy=-9-3=-12

(x^3y+xy^3)/(-xy)
=xy(x^2+y^2)/(-xy)
=-(x^2+y^2)
=-(x^2+2xy+y^2)+2xy
=-(x+y)^2+2xy
=-(-3)^2+2*(-1)
=-9-2
=-11

x+y=-3
xy=-(1+1/2)=-3/2
(x+y)^2=(-3)^2
x+y+2xy=9
x^2+y^2=9-2xy=9-2*(-3/2)=12
(x^3y+xy^3)/(-xy)=-(x^2+y^2)=-12

(x^3y+xy^3)/(-xy) = -(x^2+y^2)=-(x+y)^2+2xy=-9+2*(-3/2)=-12

xy(x^2+y^2)/(-xy)剩下的懂了吧

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