\[\boxed{\text{1217.\ }\text{еуроки}\text{-}\text{ответы}\text{\ }\text{на}\text{\ }\text{пятёрку}}\]
\[8x^{2} - 6x + n = 0 \Longrightarrow\]
\[\Longrightarrow по\ т.\ Виета:\ \left\{ \begin{matrix} x_{1} + x_{2} = \frac{3}{4} \\ x_{1} \cdot x_{2} = \frac{n}{8} \\ \end{matrix} \right.\ \ \]
\[x_{1}^{- 1} + x_{2}^{- 1} = 6\]
\[\frac{1}{x_{1}} + \frac{1}{x_{2}} = 6,\ \ \frac{x_{1} + x_{2}}{x_{1} \cdot x_{2}} = 6\]
\[\frac{3}{4}\ :\frac{n}{8} = 6,\ \ \frac{3}{4} \cdot \frac{8}{n} = 6,\ \ \]
\[\frac{6}{n} = 6,\ \ n = 1\]
\[Ответ:n = 1.\]