不等式2x+1/1-x大于等于3
问题描述：
不等式2x+1/1-x大于等于3
答
(2x+1)/(1-x)≥3
(2x+1)/(1-x)-3≥0
[2x+1-3(1-x)]/(1-x)≥0
(2x+1-3+3x)/(1-x)≥0
(5x-2)/(1-x)≥0
(5x-2)/(x-1)≤0
(5x-2)(x-1)≤0 x-1≠0
2/5≤x额 请问为何x-1不等于0分母不能为0