2x+108 chia hết cho 2x+3
=>(2x+3)+105 chia hết cho 2x+3
=>2x+3 thuộc U(105)={1;3;21;7;15;35;105}
2x+3=1=>2x=-2=>x=-1
2x+3=5=>2x=2=>x=1
2x+3=3=>2x=0=>x=0
2x+3=7=>2x=4=>x=2
2x+3=15=>2x=12=>x=6
2x+3=21=>2x=18=>x=9
2x+3=35=>2x=32=>x=16
2x+3=105=>2x=102=>x=51
vậy x E{1;2;6;9;16;51}