\[16y² - 8y - 31 = 0\]
\[D = b^{2} - 4ac =\]
\[= 64 - 4 \cdot 16 \cdot ( - 31) =\]
\[= 64 + 1984 = 2048\]
\[y_{1} = \frac{8 + 32\sqrt{2}}{32} = \frac{1}{4} + \sqrt{2} =\]
\[= 1,664\]
\[y_{2} = \frac{8 - 32\sqrt{2}}{32} = \frac{1}{4} - \sqrt{2} =\]
\[= - 1,164\]
\[Ответ:y = 1,664\ \ и\ \ \ \]
\[y = - 1,164.\]