روش دلتا $9x^2 + 3x - 2 = 0$ $\Delta = b^2 - 4ac$ $\begin{cases} a = 9 \\ b = 3 \\ c = -2 \end{cases}$ $(3)^2 - 4(9)(-2) = 9 + 72 = 81$ $x = \frac{-b \pm \sqrt{\Delta}}{2a} = \frac{-3 \pm \sqrt{81}}{2(9)} = \frac{-3 \pm 9}{18}$ $x_1 = \frac{-3 + 9}{18} = \frac{6}{18}$ $x_2 = \frac{-3 - 9}{18} = \frac{-12}{18}$