ГДЗ по математике 6 класс Мерзляк Задание 439

\[\boxed{\mathbf{439\ (438).}\mathbf{\ }Еуроки\ - \ ДЗ\ без\ мороки}\]

\[1)\ \left( 6\frac{8}{11} \cdot \frac{4}{5} \right) \cdot 1\frac{1}{4} = \frac{74}{11} \cdot \frac{4}{5} \cdot \frac{5}{4} =\]

\[= \frac{74 \cdot 4 \cdot 5}{11 \cdot 5 \cdot 4} = \frac{74}{11} = 6\frac{8}{11}\]

\[\boxed{\mathbf{439\ (}\mathbf{с}\mathbf{).}\mathbf{\ }Еуроки\ - \ ДЗ\ без\ мороки}\]

Пояснение.

Решение.

\[1)\ \frac{7^{\backslash 2}}{18} + \frac{7^{\backslash 3}}{12} = \frac{14 + 21}{36} = \frac{35}{36} \Longrightarrow\]

\[\Longrightarrow \frac{36}{35}\]

\[2)\ 2\frac{13^{\backslash 3}}{14} + 1\frac{20^{\backslash 2}}{21} =\]

\[= 2\frac{39}{42} + 1\frac{40}{42} = 3\frac{79}{42} = 4\frac{37}{42} =\]

\[= \frac{205}{42} \Longrightarrow \frac{42}{205}\]

\[3)\ \frac{13^{\backslash 2}}{60} - \frac{7^{\backslash 3}}{40} = \frac{26 - 21}{120} =\]

\[= \frac{5}{120} = \frac{1}{24} \Longrightarrow 24\]