Ответ:

а) Сократим множители:

\(\frac{18}{35}\cdot\frac{14}{27}=\frac{2}{5}\cdot\frac{2}{3}=\frac{4}{15}\).

б) Преобразуем смешанные числа в неправильные дроби:

\(9\frac{3}{7}=\frac{66}{7}\), \(1\frac{3}{11}=\frac{14}{11}\).

\(\frac{66}{7}\cdot\frac{14}{11}=6\cdot2=12\).

в) \(0{,}175=\frac{7}{40}\), \(6\frac{2}{13}=\frac{80}{13}\), \(1\frac{5}{21}=\frac{26}{21}\).

\(\frac{7}{40}\cdot\frac{80}{13}\cdot\frac{26}{21}=\frac{7\cdot2\cdot2}{21}=\frac{28}{21}=\frac{4}{3}=1\frac{1}{3}\).

г) \(1\frac{7}{24}=\frac{31}{24}\), \(1\frac{11}{21}=\frac{32}{21}\), \(1\frac{1}{15}=\frac{16}{15}\).

\(\left(\frac{31}{24}-\left(\frac{3}{4}\right)^2\right)\cdot\frac{32}{21}-\frac{16}{15}=\left(\frac{31}{24}-\frac{9}{16}\right)\cdot\frac{32}{21}-\frac{16}{15}\).

\(\frac{31}{24}-\frac{9}{16}=\frac{35}{48}\).

\(\frac{35}{48}\cdot\frac{32}{21}-\frac{16}{15}=\frac{10}{9}-\frac{16}{15}=\frac{50}{45}-\frac{48}{45}=\frac{2}{45}\).

Ответ: а) \(\frac{4}{15}\); б) 12; в) \(1\frac{1}{3}\); г) \(\frac{2}{45}\).