\[\boxed{\mathbf{60}.}\]
\[1)\ \frac{- 21}{5 - 6x} > 0\]
\[- 21 < 0 - при\ любом\ \]
\[значении\ x;\]
\[5 - 6x < 0\]
\[- 6x < - 5\]
\[x > \frac{5}{6}.\]
\[Ответ:x > \frac{5}{6}.\]
\[2)\ \frac{0,8x - 2}{x^{2} + 1} < 0\]
\[x^{2} + 1 > 0\ при\ любом\]
\[\ значении\ \ x;\]
\[0,8x - 2 < 0\]
\[0,8x < 2\]
\[x < \frac{20}{8} < \frac{5}{2}\]
\[x < 2,5.\]
\[Ответ:x < 2,5.\]