[tex]x = \frac{-b\pm\sqrt{\Delta}}{2a} = \frac{-(-8) \pm \sqrt{(-8)^2 - 4 \cdot 1 \cdot 12}}{2 \cdot 1} = \frac{8 \pm \sqrt{16}}{2} = \frac{8 \pm 4}{2} \\\\x_1 = \frac{8 + 4}{2} = \frac{12}{2} = 6 \\\\x_2 = \frac{8 - 4}{2} = \frac{4}{2} = 2[/tex]