Сократите дроби: 56/70; 24/64; 42/108; 90/162; 48/80; 121/165; 39/78; 72/96.

Делим числитель и знаменатель каждой дроби на их общий делитель:

1. \(\frac{56}{70}=\frac{56:14}{70:14}=\frac{4}{5}\);
2. \(\frac{24}{64}=\frac{24:8}{64:8}=\frac{3}{8}\);
3. \(\frac{42}{108}=\frac{42:6}{108:6}=\frac{7}{18}\);
4. \(\frac{90}{162}=\frac{90:18}{162:18}=\frac{5}{9}\);
5. \(\frac{48}{80}=\frac{48:16}{80:16}=\frac{3}{5}\);
6. \(\frac{121}{165}=\frac{121:11}{165:11}=\frac{11}{15}\);
7. \(\frac{39}{78}=\frac{39:39}{78:39}=\frac{1}{2}\);
8. \(\frac{72}{96}=\frac{72:24}{96:24}=\frac{3}{4}\).

Ответ: \(\frac{4}{5};\ \frac{3}{8};\ \frac{7}{18};\ \frac{5}{9};\ \frac{3}{5};\ \frac{11}{15};\ \frac{1}{2};\ \frac{3}{4}\).