Вариант I, Задание 2: Выполните действия: а) \(\frac{11}{18} + \frac{5}{12}\), б) \(\frac{5}{3} - \frac{3}{7}\), в) \(\frac{5}{6} - \frac{1}{9} + \frac{1}{15}\)

а) \(\frac{11}{18} + \frac{5}{12} = \frac{11 \cdot 2}{18 \cdot 2} + \frac{5 \cdot 3}{12 \cdot 3} = \frac{22}{36} + \frac{15}{36} = \frac{22+15}{36} = \frac{37}{36}\) б) \(\frac{5}{3} - \frac{3}{7} = \frac{5 \cdot 7}{3 \cdot 7} - \frac{3 \cdot 3}{7 \cdot 3} = \frac{35}{21} - \frac{9}{21} = \frac{35-9}{21} = \frac{26}{21}\) в) \(\frac{5}{6} - \frac{1}{9} + \frac{1}{15} = \frac{5 \cdot 15}{6 \cdot 15} - \frac{1 \cdot 10}{9 \cdot 10} + \frac{1 \cdot 6}{15 \cdot 6} = \frac{75}{90} - \frac{10}{90} + \frac{6}{90} = \frac{75-10+6}{90} = \frac{71}{90}\) Ответ: а) \(\frac{37}{36}\), б) \(\frac{26}{21}\), в) \(\frac{71}{90}\)