3. Запишите числа, обратные данным числам:

a) \(\frac{7}{15}\) -> \(\frac{15}{7}\); б) \(\frac{6}{17}\) -> \(\frac{17}{6}\); в) \(\frac{1}{13}\) -> 13; г) \(\frac{5}{11}\) -> \(\frac{11}{5}\); д) \(\frac{8}{21}\) -> \(\frac{21}{8}\); e) 9 -> \(\frac{1}{9}\); ж) 5 -> \(\frac{1}{5}\); з) 3 -> \(\frac{1}{3}\); и) 7 -> \(\frac{1}{7}\); м) 13 -> \(\frac{1}{13}\)