(ax+1)/(x+a)-1＞0
[(ax+1)-(x+a)]/(x+a)＞0
(a-1)(x-1)/(x+a)＞0
1.a＞1时
(x-1)/(x+a)＞0
x＞1 或者x＜-a
2.-1＜a＜1时
(x-1)/(x+a)＜0
-a＜x＜1
3 .a＜-1时
(x-1)/(x+a)＜0
1＜x＜a