3 cos^2 x - 2 sin x = 3 - 3 sin^2 x

3 cos^2 x - 2 sin x = 3 - 3 sin^2 x
3 cos^2 x + 3 sin^2 x - 2 sin x = 3
3 (cos^2 x +  sin^2 x) - 2 sin x = 3
3*1 - 2sin x = 3
2sin x= 3-3 = 0
sin x = 0
x = Arc sin 0 = kπ.