If $2 \tan ^{2} \theta-4 \sec \theta+3=0$, then $2 \sec \theta=$

If $0 < \theta < \frac{\pi}{4}$ and $8 \cos \theta+15 \sin \theta=15$, then $15 \cos \theta-8 \sin \theta=$

$\sin 20^{\circ}\left(4+\sec 20^{\circ}\right)=$

If $\sin h x=\frac{12}{5}$, then $\sin h 3 x+\cos h 3 x=$