问两道解方程

来源：百度知道 编辑：UC知道 时间：2024/05/17 15:23:44
想了老半天都不会 5/4x-(45-x)×2/3=14

这个是比例方程 (4x-42):3x=3:4

5/4x - (45-x)* 2/3 = 14
5/4x - 45* 2/3 - x * 2/3 = 14
5/4x - 2/3x - 30 = 14
5/4x - 2/3x = 14 + 30
15/12x - 8/12x = 44
7/12x = 44
x = 44 / (7/12)
x = (44 * 12) / 7
x = 528/7

.... 步骤是这样, 数字可能错了
=================================================
(4x - 42):3x = 3:4

3x = 4
x = 4/3

4x - 42 = 3
4x = 3 + 42
4x = 45
x = 45/4

45/4 不等于 4/3

...........无解

5/4x-(45-x)×2/3=14
15x-8(45-x)=14*12
23x=14*12+45+8
x=508/23

9x=16x-42*4
7x=168
x=24

化间再化间
5/4x-(45-x)*2/3=14
5/4x-30+2/3x=14
23/12x=44
x=44*12/23=528/23

2...交叉相乘
(4x-42)*4=3*3x
16x-168=9x
7x=168
x=24