\[2x^{2} - 7x - 9 < 0\]
\[2x^{2} - 7x - 9 = 0\]
\[D = 49 + 72 = 121\]
\[x_{1} = \frac{7 + 11}{4} = \frac{18}{4} = 4,5;\ \ \ \]
\[x_{2} = \frac{7 - 11}{4} = - 4\]
\[2 \cdot (x + 4)(x - 4,5) < 0\]
\[Ответ:x \in ( - 1;4,5).\]