计算(-y-x)(x+y)的结果是()A.y2-x2B.x2-y2C.-y2-2xy-x2D.x2+2xy+y2-数学

题目简介

计算(-y-x)(x+y)的结果是()A.y2-x2B.x2-y2C.-y2-2xy-x2D.x2+2xy+y2-数学

题目详情

计算(-y-x)(x+y)的结果是(  )
A.y2-x2B.x2-y2C.-y2-2xy-x2D.x2+2xy+y2
题型:单选题难度:中档来源:不详

答案

(-y-x)(x+y)
=-(x+y)2
=-y2-2xy-x2.
故选C.

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