249. Сократите: a) \(\frac{2 \cdot 3}{4 \cdot 5}\), \(\frac{2 \cdot 3}{7 \cdot 2}\), \(\frac{5 \cdot 4}{4 \cdot 9}\), \(\frac{7 \cdot 5}{2 \cdot 7}\) б) \(\frac{4 \cdot 5}{3 \cdot 6}\), \(\frac{15 \cdot 3}{11 \cdot 10}\), \(\frac{14 \cdot 9}{15 \cdot 7}\), \(\frac{2 \cdot 3}{9 \cdot 8}\)

а) Сокращаем каждую дробь:
\(\frac{2 \cdot 3}{4 \cdot 5} = \frac{6}{20} = \frac{3}{10}\)
\(\frac{2 \cdot 3}{7 \cdot 2} = \frac{3}{7}\)
\(\frac{5 \cdot 4}{4 \cdot 9} = \frac{5}{9}\)
\(\frac{7 \cdot 5}{2 \cdot 7} = \frac{5}{2}\)
б) Сокращаем каждую дробь:
\(\frac{4 \cdot 5}{3 \cdot 6} = \frac{20}{18} = \frac{10}{9}\)
\(\frac{15 \cdot 3}{11 \cdot 10} = \frac{45}{110} = \frac{9}{22}\)
\(\frac{14 \cdot 9}{15 \cdot 7} = \frac{126}{105} = \frac{6}{5}\)
\(\frac{2 \cdot 3}{9 \cdot 8} = \frac{6}{72} = \frac{1}{12}\)
Ответ:
a) \(\frac{3}{10}\), \(\frac{3}{7}\), \(\frac{5}{9}\), \(\frac{5}{2}\)
б) \(\frac{10}{9}\), \(\frac{9}{22}\), \(\frac{6}{5}\), \(\frac{1}{12}\)