а) НОЗ(16, 12) = 48: \(\frac{5}{16}=\frac{15}{48}\), \(\frac{7}{12}=\frac{28}{48}\).
б) НОЗ(21, 14) = 42: \(\frac{2}{21}=\frac{4}{42}\), \(\frac{3}{14}=\frac{9}{42}\).
в) НОЗ(15, 18, 30) = 90: \(\frac{7}{15}=\frac{42}{90}\), \(\frac{5}{18}=\frac{25}{90}\), \(\frac{11}{30}=\frac{33}{90}\).
Ответ: а) \(\frac{15}{48},\frac{28}{48}\); б) \(\frac{4}{42},\frac{9}{42}\); в) \(\frac{42}{90},\frac{25}{90},\frac{33}{90}\).