设x(x-1)-(x方-y)=-2,求二分之x方+y方,再减xy的值

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设x(x-1)-(x方-y)=-2,求二分之x方+y方,再减xy的值
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设x(x-1)-(x方-y)=-2,求二分之x方+y方,再减xy的值
设x(x-1)-(x方-y)=-2,求二分之x方+y方,再减xy的值

设x(x-1)-(x方-y)=-2,求二分之x方+y方,再减xy的值
答案为2.
上式展开,x方-x-x方+y=-2,可得:y-x=-2.即x-y=2
而要求的结果,将其乘以2,可得为x方+y方-2xy的值,这即为求(x-y)方的值.
由上式得x-y=2,所以(x-y)方为4,再除以2,就是答案,为2.
(楼主不给悬赏分,太不厚道了呀~哇啊~>3