Неравенства

$$D = 25 - 4\cdot3\cdot2 = 1 \Rightarrow \sqrt{D} = 1$$ $$x _1 = \frac{5 + 1}{6} = 1, \quad x_2 = \frac{5 - 1}{6} = \frac{2}{3}$$

$$D = 16 - 4\cdot3\cdot(-20) = 256 \Rightarrow \sqrt{D} = 16$$ $$x _1 = \frac{4 + 16}{6} = \frac{10}{3}, \quad x_2 = \frac{4 - 16}{6} = -2$$

$$5x - 1 = 0 \text{ или } 3x + 4 = 0$$ $$x = \frac{1}{5} = 0,2 \text{ или } x = -\frac{4}{3}$$

$$10x - 24 = 0 \text{ или } 7x - 4 = 0$$ $$x = 2,4 \text{ или } x = \frac{4}{7}$$

$$5 - 2x = 0 \text{ или } 39x + 5 = 0$$ $$x = 2,5 \text{ или } x = -\frac{5}{39}$$