已知x(x+1)-(x²+y)=3,求2分之x²+y²-xy的值
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![已知x(x+1)-(x²+y)=3,求2分之x²+y²-xy的值](/uploads/image/z/1730652-60-2.jpg?t=%E5%B7%B2%E7%9F%A5x%EF%BC%88x%EF%BC%8B1%EF%BC%89-%EF%BC%88x%26%23178%3B%EF%BC%8By%EF%BC%89%3D3%2C%E6%B1%822%E5%88%86%E4%B9%8Bx%26%23178%3B%2By%26%23178%3B-xy%E7%9A%84%E5%80%BC)
已知x(x+1)-(x²+y)=3,求2分之x²+y²-xy的值
已知x(x+1)-(x²+y)=3,求2分之x²+y²-xy的值
已知x(x+1)-(x²+y)=3,求2分之x²+y²-xy的值
x(x+1)-(x²+y)=3
x²+x-x²-y=3
x-y=3
2分之(x²+y²)-xy
=2分之(x²-2xy+y²)
=2分之(x-y)²
=2分之3²
=2分之9