ГДЗ по математике 6 класс Мерзляк Задание 315

\[\boxed{\mathbf{315\ (316).}\mathbf{\ }Еуроки\ - \ ДЗ\ без\ мороки}\]

\[1)\ a + \frac{1}{a} = 7\frac{1}{7}\]

\[7 + \frac{1}{7} = 7\frac{1}{7}\]

\[\Longrightarrow a = 7.\]

\[2)\ b - \frac{1}{b} = 14\frac{14}{15}\]

\[15 - \frac{1}{15} = 14\frac{14}{15}\]

\[\Longrightarrow b = 15.\]

\[\boxed{\mathbf{315\ (}\mathbf{с}\mathbf{).}\mathbf{\ }Еуроки\ - \ ДЗ\ без\ мороки}\]

\[1)\ \frac{3}{a} + \frac{9}{2a} = \frac{3 \cdot 2 + 9}{2a} = \frac{6 + 9}{2a} =\]

\[= \frac{15}{2a}\]

\[2)\ \frac{11c}{14d} + \frac{c}{21d} =\]

\[= \frac{11c \cdot 3 + c \cdot 2}{42d} = \frac{33c + 2c}{42d} =\]

\[= \frac{35c}{42d} = \frac{5c}{6d}\]

\[3)\ \frac{17p}{18q} - \frac{11p}{12q} =\]

\[= \frac{17p \cdot 2 - 11p \cdot 3}{39q} =\]

\[= \frac{34p - 33p}{39q} = \frac{p}{36q}\]