Решить уравнение: $$4.2(3z - 5) - 1.4(5z - 3) = 5.6$$

$$4.2(3z - 5) - 1.4(5z - 3) = 5.6$$ $$12.6z - 21 - 7z + 4.2 = 5.6$$ $$(12.6z - 7z) + (4.2 - 21) = 5.6$$ $$5.6z - 16.8 = 5.6$$ $$5.6z = 5.6 + 16.8$$ $$5.6z = 22.4$$ $$z = \frac{22.4}{5.6}$$ $$z = 4$$ **Ответ: z = 4**