Вычислить: а) $\dfrac{\frac{1}{30}+\frac{1}{42}}{\frac{1}{7}}$; б) $\dfrac{\frac{1}{18}-\frac{1}{21}}{\frac{5}{63}}$; в) $\dfrac{\frac{1}{35}-\frac{1}{60}}{\frac{1}{21}}$; г) $\dfrac{\frac{1}{72}-\frac{1}{99}}{\frac{5}{33}}$.

Question

$Фото задания: Вычислить: а) $\dfrac{\frac{1}{30}+\frac{1}{42}}{\frac{1}{7}}$; б) $\dfrac{\frac{1}{18}-\frac{1}{21}}{\frac{5}{63}}$;…$ Фото задания

Accepted Answer

\[\frac{\frac{1}{30}+\frac{1}{42}}{\frac{1}{7}}=\frac{\frac{7}{210}+\frac{5}{210}}{\frac{1}{7}}=\frac{\frac{2}{35}}{\frac{1}{7}}=\frac{2}{35}\cdot7=\frac{2}{5}.\]
\[\frac{\frac{1}{18}-\frac{1}{21}}{\frac{5}{63}}=\frac{\frac{7}{126}-\frac{6}{126}}{\frac{5}{63}}=\frac{\frac{1}{126}}{\frac{5}{63}}=\frac{1}{126}\cdot\frac{63}{5}=\frac{1}{10}.\]
\[\frac{\frac{1}{35}-\frac{1}{60}}{\frac{1}{21}}=\frac{\frac{12}{420}-\frac{7}{420}}{\frac{1}{21}}=\frac{\frac{1}{84}}{\frac{1}{21}}=\frac{1}{84}\cdot21=\frac{1}{4}.\]
\[\frac{\frac{1}{72}-\frac{1}{99}}{\frac{5}{33}}=\frac{\frac{11}{792}-\frac{8}{792}}{\frac{5}{33}}=\frac{\frac{1}{264}}{\frac{5}{33}}=\frac{1}{264}\cdot\frac{33}{5}=\frac{1}{40}.\]

Ответ: а) $\frac{2}{5}$; б) $\frac{1}{10}$; в) $\frac{1}{4}$; г) $\frac{1}{40}$.

Вычислить: а) \(\dfrac{\frac{1}{30}+\frac{1}{42}}{\frac{1}{7}}\); б) \(\dfrac{\frac{1}{18}-\frac{1}{21}}{\frac{5}{63}}\); в) \(\dfrac{\frac{1}{35}-\frac{1}{60}}{\frac{1}{21}}\); г) \(\dfrac{\frac{1}{72}-\frac{1}{99}}{\frac{5}{33}}\).