3. Найдите корни уравнения: a) 2x² - 5x = 0; б) Зу + 18у² = 0;

1. a) $$2x^2 - 5x = 0$$ $$x(2x - 5) = 0$$ $$x_1 = 0$$ $$2x - 5 = 0$$ $$2x = 5$$ $$x_2 = \frac{5}{2} = 2,5$$
2. б) $$3y + 18y^2 = 0$$ $$y(3 + 18y) = 0$$ $$y_1 = 0$$ $$3 + 18y = 0$$ $$18y = -3$$ $$y_2 = -\frac{3}{18} = -\frac{1}{6}$$

Ответ: a) $$x_1 = 0, x_2 = 2,5$$, б) $$y_1 = 0, y_2 = -\frac{1}{6}$$