7 5/24 - х = 2 5/16
х = 7 5/24 - 2 5/16
х = 173/24 - 37/16 Общ. знаменатель = 48
х = 346/48 - 111/48
х = 235/48
х = 4целых 43/48
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(х + 5/12) - 9/20 = 11/15
х + 5/12 - 9/20 = 11/15
х = 11/15 - 5/12 + 9/20 Общ. знаменатель = 60
х = 44/60 - 25/60 + 27/60
х = 46/60 сократим на 2
х = 23/30