25. Найдите значение выражения: а) 6/11 · 3/4 : 2 2/5 · 2 1/5; б) 9 1/3 : 7/8 · 7/16 : 14/27; в) 5/14 + 18/35 + (1 1/4 − 5/14) : (5/12)^2; г) (7/12 − 8/15)^2 + 4/5 · (7/10 − 9/16).

а) \(\frac{6}{11}\cdot\frac{3}{4}:2\frac{2}{5}\cdot2\frac{1}{5}=\frac{6}{11}\cdot\frac{3}{4}\cdot\frac{5}{12}\cdot\frac{11}{5}=\frac{3}{8}\).

б) \(9\frac{1}{3}:\frac{7}{8}\cdot\frac{7}{16}:\frac{14}{27}=\frac{28}{3}\cdot\frac{8}{7}\cdot\frac{7}{16}\cdot\frac{27}{14}=9\).

в) \(\frac{5}{14}+\frac{18}{35}+\left(\frac{5}{4}-\frac{5}{14}\right):\left(\frac{5}{12}\right)^2=\frac{61}{70}+\frac{25}{28}\cdot\frac{144}{25}=\frac{61}{70}+\frac{9}{7}=\frac{151}{70}=2\frac{11}{70}\).

г) \(\left(\frac{7}{12}-\frac{8}{15}\right)^2+\frac{4}{5}\left(\frac{7}{10}-\frac{9}{16}\right)=\left(\frac{1}{20}\right)^2+\frac{4}{5}\cdot\frac{11}{80}=\frac{1}{400}+\frac{11}{100}=\frac{9}{80}\).

Ответ: а) \(\frac{3}{8}\); б) \(9\); в) \(2\frac{11}{70}\); г) \(\frac{9}{80}\).