Trigonometry Equations. Solve for $0 \leq X \leq 360$, giving solutions correct to the nearest minute where necessary,
a) $\cos^2 A -8\sin A \cos A +3=0$
Can someone please explain how to solve this, ive tried myself and no luck. Thanks!

HINT: $\cos^2 A=\frac{1+\cos 2A}{2},$ 
$\sin A\cos A=\frac{\sin 2A}{2}$
and $\sin^2 2A+\cos^2 2A=1$
