Зделай 72

Краткий ответ:
а) \(20\); б) \(32\).

а)

\[ \frac{(7-6{,}35):6{,}5+9{,}9} {(1{,}2:36+1{,}2:0{,}25-1\frac5{16}):7\frac1{24}} \]

Числитель: \[ (7-6{,}35):6{,}5+9{,}9 =0{,}65:6{,}5+9{,}9 =0{,}1+9{,}9=10. \]

Знаменатель: \[ 1{,}2:36=\frac1{30},\qquad 1{,}2:0{,}25=\frac{24}{5}. \]

\[ \frac1{30}+\frac{24}{5}-1\frac5{16} =\frac1{30}+\frac{24}{5}-\frac{21}{16} =\frac{169}{48}. \]

\[ 7\frac1{24}=\frac{169}{24},\qquad \frac{169}{48}:\frac{169}{24}=\frac12. \]

Тогда: \[ 10:\frac12=\boxed{20}. \]

б)

\[ \frac{\left(0{,}5:1{,}25+\frac75:1\frac47-\frac3{11}\right)\cdot3} {(1{,}5+\frac14):18\frac13} \]

Числитель: \[ 0{,}5:1{,}25=\frac25, \] \[ \frac75:1\frac47=\frac75:\frac{11}{7}=\frac{49}{55}. \]

\[ \left(\frac25+\frac{49}{55}-\frac3{11}\right)\cdot3 =\left(\frac{22}{55}+\frac{49}{55}-\frac{15}{55}\right)\cdot3 =\frac{56}{55}\cdot3=\frac{168}{55}. \]

Знаменатель: \[ (1{,}5+\frac14):18\frac13 =\left(\frac32+\frac14\right):\frac{55}{3} =\frac74\cdot\frac3{55} =\frac{21}{220}. \]

\[ \frac{168}{55}:\frac{21}{220} =\frac{168}{55}\cdot\frac{220}{21} =\boxed{32}. \]

Проверка: \(20\cdot\frac12=10\), а \(32\cdot\frac{21}{220}=\frac{168}{55}\), то есть полученные результаты верны.