\[9y² + 6y - 17 = 0\ \]
\[D = b^{2} - 4ac =\]
\[= 36 - 4 \cdot 9 \cdot ( - 17) =\]
\[= 36 + 612 = 648\]
\[y_{1} = \frac{- 6 + 18\sqrt{2}}{18} = - \frac{1}{3} + \sqrt{2} =\]
\[= 1,081\]
\[y_{2} = \frac{- 6 - 18\sqrt{2}}{18} = - \frac{1}{3} - \sqrt{2} =\]
\[= - 1,746\]
\[Ответ:y = 1,081;\ \ \ \ y = - 1,746.\]