a) \(\frac{5}{9}\) и \(\frac{1}{4}\). Общий знаменатель: 9 × 4 = 36.
\(\frac{5}{9} = \frac{5 \times 4}{9 \times 4} = \frac{20}{36}\)
\(\frac{1}{4} = \frac{1 \times 9}{4 \times 9} = \frac{9}{36}\)
в) \(\frac{3}{20}\) и \(\frac{5}{24}\). Общий знаменатель: НОК(20, 24) = 120.
\(\frac{3}{20} = \frac{3 \times 6}{20 \times 6} = \frac{18}{120}\)
\(\frac{5}{24} = \frac{5 \times 5}{24 \times 5} = \frac{25}{120}\)
д) \(\frac{6}{17}\) и \(\frac{2}{11}\). Общий знаменатель: 17 × 11 = 187.
\(\frac{6}{17} = \frac{6 \times 11}{17 \times 11} = \frac{66}{187}\)
\(\frac{2}{11} = \frac{2 \times 17}{11 \times 17} = \frac{34}{187}\)
Ответ: a) \(\frac{20}{36}\) и \(\frac{9}{36}\); в) \(\frac{18}{120}\) и \(\frac{25}{120}\); д) \(\frac{66}{187}\) и \(\frac{34}{187}\)