[tex]x^{2}+3x-4 < 0\\\\a = 1, \ b = 3, \ b = -4\\\\\Delta = b^{2}-4ac = 3^{2}-4\cdot1 \cdot(-4) = 9+16 = 25\\\\\Sqrt{\Delta = \sqrt{25} = 5[/tex]
[tex]x_1 = \frac{-b-\sqrt{\Delta}}{2a} = \frac{-3-5}{2\cdot1} = -\frac{8}{2} = -4\\\\x_2 = \frac{-b+\sqrt{\Delta}}{2a} = \frac{-3+5}{2} = \frac{2}{2} = 1\\\\a > 0, \ ramiona \ paraboli \ do \ gory\\\\x \in (-4; 1)[/tex]
