\[1)\ arctg\ \frac{1 - x}{4} = \frac{\pi}{3}\]
\[\frac{1 - x}{4} = \sqrt{3}\]
\[1 - x = 4\sqrt{3}\]
\[x = 1 - 4\sqrt{3}.\]
\[Ответ:\ \ 1 - 4\sqrt{3}.\]
\[2)\ arctg\frac{1 + 2x}{3} = \frac{\pi}{4}\]
\[\frac{1 + 2x}{3} = 1\]
\[1 + 2x = 3\]
\[2x = 2\]
\[x = 1.\]
\[Ответ:\ \ 1.\]
\[3)\ arctg(2x + 1) = - \frac{\pi}{3}\]
\[2x + 1 = - \sqrt{3}\]
\[2x = - 1 - \sqrt{3}\]
\[x = - \frac{1 + \sqrt{3}}{2}.\]
\[Ответ:\ - \frac{1 + \sqrt{3}}{2}.\]
\[4)\ arctg(2 - 3x) = - \frac{\pi}{4}\]
\[2 - 3x = - 1\]
\[3x = 3\]
\[x = 1.\]
\[Ответ:\ \ 1.\]