解方程: 78×3x=3.6 x÷1.98=0.4 (4.5-x)×0.375=0.75 1/2x+2/3x=14 x-0.52x=3.2×0.15 1/2x+25%=10.

问题描述:

解方程:

78×3x=3.6 x÷1.98=0.4 (4.5-x)×0.375=0.75
1
2
x+
2
3
x=14
x-0.52x=3.2×0.15
1
2
x+25%=10.

①78×3x=3.6
       234x=3.6
  234x÷234=3.6÷234
          x=

2
145

    ②x÷1.98=0.4
x×1.98÷1.98=0.4×1.98
            x=0.792
     ③(4.5-x)×0.375=0.75
(4.5-x)×0.375÷0.375=0.75÷0.375
                 4.5-x=2
               4.5-x+x=2+x
                 2+x-2=4.5-2
                     x=2.5
1
2
x+
2
3
x=14
    
7
6
x=14
  
7
6
6
7
=14×
6
7

       x=12
  ⑤x-0.52x=3.2×0.15
      0.48x=0.48
0.48x÷0.48=0.48÷0.48
          x=1
     ⑥
1
2
x+25%=10
     0.5x+0.25=10
0.5x+0.25-0.25=10-0.25
          0.5x=9.75
       0.5x×2=9.75×2
             x=19.5