7. Сократите дроби, используя признаки делимости: \(\frac{100}{25};\ \frac{75}{120};\ \frac{36}{171};\ \frac{153}{84}\).

\[\frac{100}{25}=4.\]

\[\frac{75}{120}=\frac{75:15}{120:15}=\frac{5}{8}.\]

\[\frac{36}{171}=\frac{36:9}{171:9}=\frac{4}{19}.\]

\[\frac{153}{84}=\frac{153:3}{84:3}=\frac{51}{28}.\]

Ответ: \(4;\ \frac{5}{8};\ \frac{4}{19};\ \frac{51}{28}\).