If you mean (2/3)x - 1, then there's nothing x can't be, so the answer is (-Infinity,Infinity)
If you mean (2/(3x)) - 1 then x can be anything but 0, so the answer is (-Infinity,Infinity), x not = 0
(note: I don't know to express punching out a single value in interval notation)
If you mean 2/(3x-1), then 3x-1 can't be 0, so x can't be 1/3, so the answer is (-Infinity,Infinity), x not = 1/3