Варіант 3. Номер 68

1) (x + 45) – 15 = 34
x + 45 = 34 + 15
x + 45 = 49
x = 49 – 15
x = 4

2) (x – 56) – 24 = 17
x – 56 = 17 + 24
x – 56 = 41
x = 41 + 56
x = 97

3) (x – 27) + 35 = 81
x – 27 = 81 – 35
x – 27 = 46
x = 46 + 27
x = 73

4) 478 – (256 + x) = 143
256 + x = 478 – 143
256 + x = 335
x = 335 – 256
x = 79

5) 659 – (345 – x) = 427
345 – x = 659 – 427
345 – x = 232
x = 345 – 232
x = 113

6) 791 – (x – 298) = 683
x – 298 = 791 – 683
x – 298 = 108
x = 108 + 298
x = 406