х+5/23=19/23     х-15/28=3/28х+17/35=23/35    31/35-y=11/358/17+y=16/17   

1) х + 5/23 = 19/23
х = 19/23 - 5/23
х = 14/23
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14/23 + 5/23 = 19/28

2) х + 17/35 = 23/35
х = 23/35 - 17/35
х = 6/35
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6/35 + 17/35 = 23/35

3) 8/17 + у = 16/17
у = 16/17 - 8/17
у = 8/17
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8/17 + 8/17 = 16/17

4) х - 15/28 = 3/28
х = 15/28 + 3/28
х = 18/28
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18/28 - 15/28 = 3/28

5) 31/35 - у = 11/35
у = 31/35 - 11/35
у = 20/35
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31/35 - 20/35 = 11/35

6) 47/48 - х = 31/48
х = 47/48 - 31/48
х = 16/48
-----------
47/48 - 16/48 = 31/48

Х + 5/23 = 19/23
х = 19/23 - 5/23
х = 14/23
_____________
14/23 + 5/23 = 19/28

х + 17/35 = 23/35
х = 23/35 - 17/35
х = 6/35
_______________
6/35 + 17/35 = 23/35

8/17 + у = 16/17
у = 16/17 - 8/17
у = 8/17
_____________
8/17 + 8/17 = 16/17

х - 15/28 = 3/28
х = 15/28 + 3/28
х = 18/28
_____________
18/28 - 15/28 = 3/28

31/35 - у = 11/35
у = 31/35 - 11/35
у = 20/35
______________
31/35 - 20/35 = 11/35

47/48 - х = 31/48
х = 47/48 - 31/48
х = 16/48
_____________
47/48 - 16/48 = 31/48