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求x的值3.5x+1.5x=250.75:x=3:122.6×30-1.3x=0.

题目详情
求x的值
3.5x+1.5x=25
0.75:x=3:12
2.6×30-1.3x=0.
▼优质解答
答案和解析
(1)3.5x+1.5x=25,
        (3.5+1.5)x=25,
               5x=25,
           5x÷5=25÷5,
                 x=5;
(2)0.75:x=3:12,
          3x=0.75×12,
          3x=9,
       3x÷3=9÷3,
           x=3;
(3)2.6×30-1.3x=0,
          78-1.3x=0,
     78-1.3x+1.3x=0+1.3x,
             1.3x=78,
        1.3x÷1.3=78÷1.3,
                x=60.