答
(a-9)/5的绝对值与1/3a+2的绝对值相等
|(a-9)/5|=|1/3a+2|
∴(a-9)/5=1/3a+2或-(a-9)/5=1/3a+2
当(a-9)/5=1/3a+2
a-9=5/3a+10
-19=2/3a
a=-57/2
当-(a-9)/5=1/3a+2
9-a=5/3a+10
-1=8/3a
a=-3/8
综上
a=-3/8或-57/2