x(x-1)-(x²-y)=-2,求 二分之(x²+y²)—xy的值
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![x(x-1)-(x²-y)=-2,求 二分之(x²+y²)—xy的值](/uploads/image/z/1730650-58-0.jpg?t=x%28x-1%29-%EF%BC%88x%26%23178%3B-y%29%3D-2%2C%E6%B1%82+%E4%BA%8C%E5%88%86%E4%B9%8B%EF%BC%88x%26%23178%3B%2By%26%23178%3B%29%E2%80%94xy%E7%9A%84%E5%80%BC)
x(x-1)-(x²-y)=-2,求 二分之(x²+y²)—xy的值
x(x-1)-(x²-y)=-2,求 二分之(x²+y²)—xy的值
x(x-1)-(x²-y)=-2,求 二分之(x²+y²)—xy的值
即x²-x-x²+y=-2
-x+y=-2
x-y=2
所以原式=(x²-2xy+y²)/2
=(x-y)²/2
=2²/2
=2
即x²-x-x²+y=-2
-x+y=-2
x-y=2
所以原式=(x²-2xy+y²)/2
=(x-y)²/2
=2²/2
=2
x(x-1)-(x²-y)=-2化简,-x+y=-2
代数式(x²+y²)/2—xy=(x²+y²—2xy)/2=(x-y)²/2=2