\[\boxed{\mathbf{1559}\mathbf{.}}\]
\[1)\ y = \frac{1}{x + 1} - \frac{1}{x - 1};\]
\[F(x) = \frac{1}{1}\ln|x + 1| - \frac{1}{1}\ln|x - 1| =\]
\[= \ln\left| \frac{x + 1}{x - 1} \right| + C;\]
\[Ответ:\ \ F(x) = \ln\left| \frac{x + 1}{x - 1} \right| + C.\]
\[2)\ y = \frac{3}{4x - 1};\]
\[F(x) = 3 \bullet \frac{1}{4}\ln|4x - 1| =\]
\[= \frac{3}{4}\ln|4x - 1| + C.\]
\[Ответ:\ \ F(x) = \frac{3}{4}\ln|4x - 1| + C.\]