Yes good. But there are more solutions when you consider angles coterminal with these.
So t = 2pi/3 +2k pi or 4pi/3 +2k pi where k is an integer.
But here t = 3x
So 3x = 2pi/3 + 2kpi or 4pi/3 + 2kpi
Divide both sides by 3
x = 2pi/9 +2kpi/3 or 4pi/9 + 2kpi/3
Now let k=0, 1, 2, etc until you pick up all the solutions between 0 and pi