a∈(-2/5,1/3] 思路如下：当5a+2＞0时,即a＞-2/5原分式可变为2a+3≥5a+2解得a∈(-2/5,1/3] 当5a+2＜0时,原分式可变为2a+3≤1解得无解综上,得到a∈(-2/5,1/3]
