Question

${2x}^{2} + 5x - 7 < 0$
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Answer 1

${2x}^{2} + 5x - 7 < 0 \\ D = {5}^{2} +4 \times 2 \times 7 = 81 \\ \left[ \begin{gathered} x_{1} = \frac{-5+9}{4}=1\\ x_{2} = \frac{-5-9}{4}=-3,5 \end{gathered} \right.\\ x \in (-3,5;1)$