4/15 + (х - 1 7/15) = 4/15
х - 1 7/15 = 4/15 - 4/15
х - 1 7/15 = 0
х = 0 + 1 7/15
х = 1 целая 7/15
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Проверка: 4/15 + (1 7/15 - 1 7/15) = 4/15
4/15 + 0 = 4/15
4/15 = 4/15
4/15 + (х - 1 7/15) = 4/15
х - 1 7/15 = 4/15 - 4/15
х - 1 7/15 = 0
х = 0 + 1 7/15
х = 1 целая 7/15
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Проверка: 4/15 + (1 7/15 - 1 7/15) = 4/15
4/15 + 0 = 4/15
4/15 = 4/15