Решите квадратное уравнение: 2x^2-5x-7=0.

\[2x^{2} - 5x - 7 = 0\]

\[D = ( - 5)^{2} - 4 \cdot 2 \cdot ( - 7) =\]

\[= 25 + 56 = 81\]

\[x_{1} = \frac{5 + \sqrt{81}}{2 \cdot 2} = \frac{5 + 9}{4} = \frac{14}{4} =\]

\[= \frac{7}{2} = 3,5\]

\[x_{2} = \frac{5 - \sqrt{81}}{2 \cdot 2} = \frac{5 - 9}{4} = \frac{- 4}{4} =\]

\[= - 1\]

\[Ответ:3,5;\ - 1.\]