(x-1)/(x+1)＜0
(x-1)(x+1)＜0 (左右同时乘以(x+1)^2)
x∈(-1,1)
(x-1)/(x+1)=0
x=1
(x-1)/(x+1)＞0
(x-1)(x+1)＞0 (左右同时乘以(x+1)^2)
x∈(-∞,-1)∪(1,+∞)