分解因式:2xy-x2-y2正确的结果是( )A.x(y-x)+y(x-y)B.(-x-y)2C.-(x-y)2D.-(x+y)2
题型:单选题难度:一般来源:不详
分解因式:2xy-x2-y2正确的结果是( )A.x(y-x)+y(x-y) | B.(-x-y)2 | C.-(x-y)2 | D.-(x+y)2 |
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答案
2xy-x2-y2=-(x2-2xy+y2)=-(x-y)2. 故选C |
举一反三
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