问题
解答题
设a(a-1)-(a2-b)=2,求
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答案
∵a(a-1)-(a2-b)=2,进行整理a2-a-a2+b=2,得b-a=2,
∴
-ab=a2+b2 2
=a2+b2-2ab 2
=2.(a-b)2 2
设a(a-1)-(a2-b)=2,求
|
∵a(a-1)-(a2-b)=2,进行整理a2-a-a2+b=2,得b-a=2,
∴
-ab=a2+b2 2
=a2+b2-2ab 2
=2.(a-b)2 2