2/5x+21=3/4x 这个方程怎么解
来源:学生作业帮 编辑:搜搜做题作业网作业帮 分类:数学作业 时间:2024/07/17 03:35:14
2/5x+21=3/4x 这个方程怎么解
![2/5x+21=3/4x 这个方程怎么解](/uploads/image/z/6166521-9-1.jpg?t=2%2F5x%2B21%3D3%2F4x+%E8%BF%99%E4%B8%AA%E6%96%B9%E7%A8%8B%E6%80%8E%E4%B9%88%E8%A7%A3)
不知你的X是在分母还是分子
如果是分子:
(2/5)X + 21 = (3/4)X
(2/5)X - (3/4)X = -21
0.4X - 0.75X = -21
-0.35X = -21
X = -21 ÷ (-0.35)
X = 60
如果是分母:
2/5X + 21 = 3/4X
2/5 + 21X = 3/4
21x = 3/4 - 2/5
21X = 15/20 - 8/20
X = 7/20 ÷ 21
X = 1/60
如果是分子:
(2/5)X + 21 = (3/4)X
(2/5)X - (3/4)X = -21
0.4X - 0.75X = -21
-0.35X = -21
X = -21 ÷ (-0.35)
X = 60
如果是分母:
2/5X + 21 = 3/4X
2/5 + 21X = 3/4
21x = 3/4 - 2/5
21X = 15/20 - 8/20
X = 7/20 ÷ 21
X = 1/60