\[\boxed{\mathbf{340}\mathbf{.}}\]
\[1)\ \log_{3}(5x + 3) = \log_{3}(7x + 5)\]
\[5x + 3 = 7x + 5\]
\[- 2x = 2\ \]
\[x = - 1.\]
\[имеет\ смысл\ при:\]
\[5x + 3 > 0\]
\[5x > - 3\ \]
\[x > - 0,6.\]
\[Ответ:\ \ решений\ нет.\]
\[2)\log_{\frac{1}{2}}(3x - 1) = \log_{\frac{1}{2}}(6x + 8)\]
\[3x - 1 = 6x + 8\]
\[- 3x = 9\ \]
\[x = - 3.\]
\[имеет\ смысл\ при:\]
\[3x - 1 > 0\]
\[3x > 1\]
\[x > \frac{1}{3}.\]
\[Ответ:\ \ решений\ нет.\]