\[4 - \sqrt{17}\ \ и\ \ 4 + \sqrt{17}\]
\[x_{1} + x_{2} =\]
\[= 4 - \sqrt{17} + 4 + \sqrt{17} = 8;\]
\[x_{1} \cdot x_{2} = \left( 4 - \sqrt{17} \right)\left( 4 + \sqrt{17} \right) =\]
\[= 16 - 17 = - 1.\]
\[Уравнение:\]
\[x^{2} - 8x - 1 = 0.\]