PT $\Leftrightarrow sin(2x+\frac{\pi}{2})+6=\sqrt3sin2x+10(1-cos(x+\frac{\pi}{6}))$$\Leftrightarrow cos 2x-\sqrt3sin2x+6+10cos(x+\frac{\pi}{6})=0$
$\Leftrightarrow 2cos(2x+\frac{\pi}{3})+10cos(x+\frac{\pi}{6})+6=0$
$\Leftrightarrow 2cos^2(x+\frac{\pi}{6})+5cos(s+\frac{\pi}{6})+2=0$
$\Leftrightarrow (cos(x+\frac{\pi}{6})+2)(2cos(x+\frac{\pi}{6})+1))=0$
Đến đây okey