đề:... \Leftrightarrow 2\sqrt{3} \sin ^{2}x -\sqrt{3}\cos x +\sin 2x-3\sin x=0 \Leftrightarrow 2\sqrt{3}\sin ^{2}x+2\sin x\cos x -\sqrt{3}\cos x-3\sin x=0 \Leftrightarrow 2\sin x.(\sqrt{3}\sin x+\cos x) -\sqrt{3}(\sqrt{3}\sin x+\cos x)=0 \Leftrightarrow (2\sin x-\sqrt{3}).(\sqrt{3}\sin x+\cos x)=0