(х + 4 9/11) - 5 6/11 = 1 8/11
х + 4 9/11 - 5 6/11 = 1 8 /11
х + 53/11 - 61/11 = 19/11
х - 8/11 = 19/11
х = 19/11 + 8/11
х = 27/11 или 2 5/11
проверка:
(2 5/11 + 4 9/11) - 5 6/11 = 1 8/11
(27/11 + 53/11) - 61/11 = 19/11
80/11 - 61/11 = 19/11
19/11 = 19/11