第一题(a+1)x-1>a可以得到x>1(a+1)x>a+1得到x>1说明a+1>0所以a>-1第二题2x-b>=0x>=b/2x+a<=0x<=-a解集是b/2<=x<=a同时3<=x<=4所以b/2=3b=6a=4ax+b＜04x+6<0解集x<-3/2第三题x-a>03-2x>0x>ax<3/2解集是a正整数解有6个请查看题目，a
