\[1)\ \left( 3 - 4\sin x \right)\left( 3 + 4\cos x \right) = 0\]
\[3 - 4\sin x = 0\]
\[4\sin x = 3\]
\[\sin x = \frac{3}{4}\]
\[x = ( - 1)^{n} \bullet \arcsin\frac{3}{4} + \pi n.\]
\[3 + 4\cos x = 0\]
\[4\cos x = - 3\]
\[\cos x = - \frac{3}{4}\]
\[x = \pm \left( \pi - \arccos\frac{3}{4} \right) + 2\pi n.\]
\[Ответ:\ \ ( - 1)^{n} \bullet \arcsin\frac{3}{4} + \pi n;\ \]
\[\text{\ \ \ \ \ \ \ \ \ \ } \pm \left( \pi - \arccos\frac{3}{4} \right) + 2\pi n.\]
\[2)\ (tg\ x + 3)(tg\ x + 1) = 0\]
\[1)\ tg\ x + 3 = 0\]
\[tg\ x = - 3\]
\[x = - arctg\ 3 + \pi n.\]
\[2)\ tg\ x + 1 = 0\]
\[tg\ x = - 1\]
\[x = - arctg\ 1 + \pi n = - \frac{\pi}{4} + \pi n.\]
\[Ответ:\ - arctg\ 3 + \pi n;\ \]
\[\text{\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ } - \frac{\pi}{4} + \pi n.\]