х+8=12. а-7=30. 47-b=34

х + 8 = 12

х = 12 - 8

х = 4

а - 7 = 30

а = 30 + 7

а = 37

47 - b = 34

b = 47 - 34

b = 13

Х= 12-8

Х=4

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4+8=12

12=12

а=30-7

а= 23

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23+7=30

30=30

b=47-34

b=13

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47-13=34

34=34