分两种情况1“当a=2时直线为：x=1/5不经过第二象限满足
2"当a不=2时直线为y=(3a-1)/(a-2)x-1/(a-2),画图可知当a=1/3时y=3/5不满足,当a不=1/3则(3a-1)/(a-2)>0 -1/(a-2)2
综上：a>=2