Задание 292 Вариант 2 Самостоятельная работа ГДЗ Дидактические материалы Чесноков 6 класс (Математика)

а)

$$\frac{1}{21}y-\frac{1}{3}y-\frac{1}{14}y=\frac{5}{14}$$
$$\left(\frac{1}{21}-\frac{1}{3}-\frac{1}{14}\right)y=\frac{5}{14}$$
$$\left(\frac{2}{42}-\frac{14}{42}-\frac{3}{42}\right)y=\frac{5}{14}$$
$$-\frac{15}{42}y=\frac{5}{14}$$
$$-\frac{5}{14}y=\frac{5}{14}$$
$$y=\frac{5}{14}:\left(-\frac{5}{14}\right)$$
$$y=-1$$

Ответ: $$y=-1$$.

б)

$$0{,}4z-\frac{5}{7}z=4{,}4$$
$$\left(0{,}4-\frac{5}{7}\right)z=4{,}4$$
$$\left(\frac{4}{10}-\frac{5}{7}\right)z=4{,}4$$
$$\left(\frac{2}{5}-\frac{5}{7}\right)z=\frac{44}{10}$$
$$\left(\frac{14}{35}-\frac{25}{35}\right)z=\frac{22}{5}$$
$$-\frac{11}{35}z=\frac{22}{5}$$
$$z=\frac{22}{5}:\left(-\frac{11}{35}\right)$$
$$z=\frac{22\cdot 35}{5\cdot(-11)}$$
$$z=-14$$

Ответ: $$z=-14$$.