3sin3x+2=4

3 sin 3x = 2
sin 3x = 2/3, so 3x is in I or in II
reference angle = 41.81..°

so 3x = 41.81 or 3x = 138.19°
x = 13.937° or x = 46.063°

for more angles add/subtract 120° to each answer to obtain as many solutions as you want.