5/12-7/9у=10 5/12-3у

5/12 - 7/9у = 10 5/12 - 3у- 7/9у + 3у = 10 5/12 - 5/122 2/9у = 1020/9у = 10у = 10 : 20/9у = 10 * 9/20у = 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