[tex]\displaystyle\bf\\x^{2} +34x-17=0\\\\Teorema \ Vieta \ :\\\\x_{1} + x_{2} =-34\\\\x_{1} \cdot x_{2} =-17\\\\\\\frac{1}{x_{1} }+\frac{1}{x_{2} } =\frac{x_{1} +x_{2} }{x_{1} \cdot x_{2} }=\frac{-34}{-17} =2\\\\\\Otvet \ : \ \frac{1}{x_{1} }+\frac{1}{x_{2} } =2[/tex]