3<=（a-2）
5<=a
x-3a-1<=5
x<=6+3a
3<=x<=5
-2<=a
-1/3<=a
所以：a ≥ -2已知条件中3<=(a-2)x-3a-1<=5，的x是（a-2）乘以x3<=（a-2）x-3a-1<=5这个呢，是-3a-1<=5 还是x-3a-1<=5？？ 3<=x<=5,就是中间是一个试子，两边是这个式子的上下取值范围x-3a-1<=5 那不还是这个吗？你这个式子中x前还得乘以（a-2）呢3<=（a-2）x-3a-1<=5， 3<=x<=53<=（a-2）x-3a-14<=ax-2x -3a4<=a(x-3)-2x当x=310<=0不合理 当x=514<=2a7<=a（a-2）x-3a-1<=5a(x-3)-2x <=6 当x=3a可以取任何数当x=5a(x-3)-2x <=6a<=8所以，8 ≥a ≥ 7