已知x^2-xy=60,xy-y^2=40,求代数式x^2-y^2和x^-2xy+y^2的值快算式和答案
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![已知x^2-xy=60,xy-y^2=40,求代数式x^2-y^2和x^-2xy+y^2的值快算式和答案](/uploads/image/z/569087-71-7.jpg?t=%E5%B7%B2%E7%9F%A5x%5E2-xy%3D60%2Cxy-y%5E2%3D40%2C%E6%B1%82%E4%BB%A3%E6%95%B0%E5%BC%8Fx%5E2-y%5E2%E5%92%8Cx%5E-2xy%2By%5E2%E7%9A%84%E5%80%BC%E5%BF%AB%E7%AE%97%E5%BC%8F%E5%92%8C%E7%AD%94%E6%A1%88)
已知x^2-xy=60,xy-y^2=40,求代数式x^2-y^2和x^-2xy+y^2的值快算式和答案
已知x^2-xy=60,xy-y^2=40,求代数式x^2-y^2和x^-2xy+y^2的值
快算式和答案
已知x^2-xy=60,xy-y^2=40,求代数式x^2-y^2和x^-2xy+y^2的值快算式和答案
x^2-xy=60,xy-y^2=40,
x^2-y^2
=(x^2-xy)+(xy-y^2)
=60+40
=100
x^2-2xy+y^2
=(x^2-xy)-(xy-y^2)
=60-40
=20