• 求值:(1)0.25-2+(278)23+lg4+2lg5-√(-3)2(2)log225?log3116?log519.试题及答案-解答题-云返教育

    • 试题详情

      求值:
      (1)0.25
      -2+(
      27
      8
      )
      2
      3
      +lg4+2lg5-
      (-3)2

      (2)log
      225?log3
      1
      16
      ?log5
      1
      9

      试题解答


      见解析
      解:(1)0.25-2+(
      27
      8
      )
      2
      3
      +lg4+2lg5-
      (-3)2

      =(0.5
      2)-2+[(
      3
      2
      )3]
      2
      3
      +2(lg2+lg5)-
      9

      =16+
      9
      4
      +2-3=
      69
      4

      (2)log
      225?log3
      1
      16
      ?log5
      1
      9

      =2log
      25?log32-4?log53-2
      =16×
      lg5
      lg2
      ×
      lg2
      lg3
      ×
      lg3
      lg5
      =16.
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