问题
解答题
先化简,再求值:y(x+y)+(x-y)2-x2-2y2,其中x=-
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答案
y(x+y)+(x-y)2-x2-2y2,
=xy+y2+x2-2xy+y2-x2-2y2,
=-xy,
当x=-
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1 |
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先化简,再求值:y(x+y)+(x-y)2-x2-2y2,其中x=-
|
y(x+y)+(x-y)2-x2-2y2,
=xy+y2+x2-2xy+y2-x2-2y2,
=-xy,
当x=-
1 |
3 |
1 |
3 |