4 8\13 - х = 1 5\13

х= 4 8\13 - 1 5\13

х=3 3\13

2 11\15 + х = 5 2\15

х = 5 2\15 - 2 11\15

х = 2 6\15 

4 8/13-х=1 5/13

-х=1 5/13-4 8/13

-х=-3 3/13

х=3 3/13

2 11/15+х=5 2/15

41/15+х=77/15

х=77/15-41/15

х=36/15

х=12/5

х=2 2/5