HI

you started off well .

**

Can you pick it up from here ? Just remember that the range is 0<x<2pi which implies 0<3x<6pi

Note that at ** , you cant cancel off the sin 3x at both sides or else you would be missing solutions because you are ignoring the possibility of

sin 3x=0

Its like , you cannot cancel the x so that x=1/2 , this is wrong .