\[x^{2} - 9x + 11 = 0\ \]
\[x_{1} + x_{2} = 9\]
\[x_{1} \cdot x_{2} = 11\]
\[\frac{1}{x_{1}} + \frac{1}{x_{2}} = \frac{x_{1} + x_{2}}{x_{1} \cdot x_{2}} = \frac{9}{11}\]