y=(2x+2/3-11/3)/(3x+1)
=(2x+2/3)/(3x+1)-(11/3)/(3x+1)
=2/3-(11/3)/(3x+1)
(11/3)/(3x+1)≠0
所以y≠2/3
解法二
3xy-y=2x-3
3yx-2x=y-3
x(3y-2)=y-3
x=(y-3)/(3y-2)
所以y≠2/3