(х + 4 5/12) * 1/3 = 6 1/3
х + 4 5/12 = 6 1/3 : 1/3 = 19/3 * 3 = 19
х = 19 - 4 5/12 = 18 12/12 - 4 5/12 = 14 7/12
х = 14 целых 7/12
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Проверка(14 7/12 + 4 5/12) * 1/3 = 6 1/3
19 * 1/3 = (6*3+1)/3
19/3 = 19/3