3 1/16 : (х - 5/16) = 7/8
х - 5/16 = 3 1/16 : 7/8 = 49/16 * 8/7 = (7*1)/(2*1) = 7/2 = 3 1/2
х = 3 1/2 + 5/16 = 3 8/16 + 5/16 = 3 13/16
х = 3 13/16
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Проверка: 3 1/16 : (3 13/16 - 5/16) = 7/8
3 1/16 : 3 8/16 = 7/8
49/16 : 56/16 = 7/8
49/16 * 16/56 = 7/8
49/56 = 7/8