Ответ Проверено экспертом Автор - prettypushkova 13/21 - (х - 2 5/7) = 3/14х - 2 5/7 = 13/21 - 3/14х - 2 5/7 = 26/42 - 9/42х - 2 5/7 = 17/42х = 17/42 + 2 5/7х = 17/42 + 2 30/42х = 2 47/42х = 3 5/42