• 计算(250+0.9+0.8+0.7)2-(250-0.9-0.8-0.7)2之值为何?( )试题及答案-单选题-云返教育

    • 试题详情

      计算(250+0.9+0.8+0.7)2-(250-0.9-0.8-0.7)2之值为何?(  )

      试题解答


      D
      解:(250+0.9+0.8+0.7)2-(250-0.9-0.8-0.7)2
      =(250+2.4)
      2-(250-2.4)2
      =[(250+2.4)+(250-2.4)][(250+2.4)-(250-2.4)]
      =500×4.8
      =2400.
      故选D.
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