5/12-7/9у=10 5/12-3у

5/12 - 7/9у = 10 5/12 - 3у - 7/9у + 3у = 10 5/12 - 5/12 2 2/9у = 10 20/9у = 10 у = 10 : 20/9 у = 10 * 9/20 у = 9/2 = 4 целых 1/2 = 4,5 --------------------------------------- Проверка: 5/12 - 7/9 * 9/2 = 10 5/12 - 3 * 9/2                   5/12 - 7/2 = 10 5/12 - 27/2                   5/12 - 42/12 = 125/12 - 162/12                   - 37/12 = - 37/12