Решите неравенство 2x^2-7x-9<0.

Ответ:

\[2x^{2} - 7x - 9 < 0\]

\[2x^{2} - 7x - 9 = 0\]

\[D = 49 + 72 = 121\]

\[x_{1} = \frac{7 + 11}{4} = \frac{18}{4} = 4,5;\ \ \ \]

\[x_{2} = \frac{7 - 11}{4} = - 4\]

\[2 \cdot (x + 4)(x - 4,5) < 0\]

\[Ответ:x \in ( - 1;4,5).\]