\[\boxed{\mathbf{59}\mathbf{.}}\]
\[\textbf{а)}\ f(x) = \ln{3x};\ \ x > 0\]
\[f^{'}(x) = \frac{1}{3x} \cdot 3 = \frac{1}{x}.\]
\[\textbf{б)}\ f(x) = \ln(5 - 2x);\]
\[\ \ 5 - 2x > 0;\ \ x < 2,5\]
\[f^{'}(x) = \frac{1}{5 - 2x} \cdot ( - 2) = \frac{2}{2x - 5}.\]
\[\textbf{в)}\ f(x) = \log_{5}( - 3x - 1);\ \]
\[- 3x - 1 > 0;\ \ x < - \frac{1}{3}\]
\[f^{'}(x) = \frac{1}{( - 3x - 1)\ln 5} \cdot ( - 3) =\]
\[= \frac{3}{(3x + 1)\ln 5}.\]
\[\textbf{г)}\ f(x) = \lg(2x + 4);\ \ \ \]
\[2x + 4 > 0;\ \ x > - 2\]
\[f^{'}(x) = \frac{1}{(2x + 4)\ln 10} \cdot 2 =\]
\[= \frac{1}{(x + 2)\ln 10}.\]