\[\boxed{\mathbf{663}\mathbf{.}}\]
\[1)\ 2\sin{2x} = 3\cos{2x}\ \ \ |\ :\cos{2x}\]
\[2\ tg\ 2x = 3\]
\[tg\ 2x = \frac{3}{2}\]
\[2x = arctg\frac{3}{2} + \pi n\]
\[x = \frac{1}{2} \bullet \left( \text{arctg}\frac{3}{2} + \pi n \right)\]
\[x = \frac{1}{2}\text{arctg}\frac{3}{2} + \frac{\text{πn}}{2}.\]
\[Ответ:\ \ \frac{1}{2}\text{arctg}\frac{3}{2} + \frac{\text{πn}}{2}.\]
\[2)\ 4\sin{3x} + 5\cos{3x} = 0\text{\ \ }\ \ |\ :\cos{3x}\]
\[4\ tg\ 3x + 5 = 0\]
\[4\ tg\ 3x = - 5\]
\[tg\ 3x = - \frac{5}{4}\]
\[3x = - arctg\frac{5}{4} + \pi n\]
\[x = \frac{1}{3} \bullet \left( - arctg\frac{5}{4} + \pi n \right)\]
\[x = - \frac{1}{3}\text{arctg}\frac{5}{4} + \frac{\text{πn}}{3}.\]
\[Ответ:\ - \frac{1}{3}\text{arctg}\frac{5}{4} + \frac{\text{πn}}{3}.\]