3. Решите уравнение: a) x + 3,12 = -5,43 б) 3,69 : y = -1,83 в) x * (-2,3) = -46 г) 7/9 * y + 11/12 = 13/18

Решение: a) $$x + 3,12 = -5,43$$ $$x = -5,43 - 3,12$$ $$x = -8,55$$ б) $$3,69 : y = -1,83$$ $$y = 3,69 : (-1,83)$$ $$y = -2,01639344262 \approx -2,02$$ в) $$x \cdot (-2,3) = -46$$ $$x = -46 : (-2,3)$$ $$x = 20$$ г) $$\frac{7}{9}y + \frac{11}{12} = \frac{13}{18}$$ $$\frac{7}{9}y = \frac{13}{18} - \frac{11}{12}$$ $$\frac{7}{9}y = \frac{26}{36} - \frac{33}{36}$$ $$\frac{7}{9}y = -\frac{7}{36}$$ $$y = -\frac{7}{36} : \frac{7}{9}$$ $$y = -\frac{7}{36} \cdot \frac{9}{7}$$ $$y = -\frac{1}{4}$$ Ответ: a) **x = -8,55** б) **y ≈ -2,02** в) **x = 20** г) **y = -1/4**