(x+15)/(x+100-15)=4/5 解方程
问题描述：
(x+15)/(x+100-15)=4/5 解方程
答
x=265
答
（x+15）/(x+100-15)=4/5
（x+15）/(x+85)=4/5
5*(x+15)=4*(x+85)
5x+75=4x+340
x=265
答
简便方法:
(x+15)/(x+100-15)=4/5
(x+15)/(x+15+70)=4/5
(x+15)/70=4
x=265
答
（x+15)/(x+100-15)=4/5
4（x+100-15）=5（x+15）
4x+340=5x+75
-x=-265
x=265
答
(x+15)/(x+100-15)=4/5
(x+15)/(x+85)=4/5
5(x+15)=4(x+85)
5x+75=4x+340
5x-4x=340-75
x=265