I am assuming you want to solve for x:-
Now cosec^2 2x = 1 - cot^2 2x so the equation becomes
3 cosec^2(2x) + 2 cosec 2x = cosec^2 2x
2 cosec^2 2x + 2 cosec 2x = 0
2 cosec 2x ( cosec 2x + 1) = 0
so 2 cosec 2x = 0 or cosec 2x = -1
cosec 2x = 0 or cosec 2x = -1
cosec 2x = 0 is indeterminate so we ignore the first one
cosec 2x = -1 can be written as 1 / sin 2x = -1
so sin 2x = -1
giving 2x = 270 degrees
Therefore x = 135 degrees answer
