Варіант 3. Номер 121

1) 7 · (x – 9) = 63
x – 9 = 63 : 7
x – 9 = 9
x = 9 + 9
x = 18

2) 32 · (x + 14) = 736
x + 14 = 736 : 32
x + 14 = 23
x = 23 – 14
x = 9

3) 17 · (3x – 16) = 238
3x – 16 = 238 : 17
3x – 16 = 14
3x = 14 + 16
3x = 30
x = 30 : 3
x = 10

4) 8 · (133 – 5x) = 864
133 – 5x = 864 : 8
133 – 5x = 108
5x = 133 – 108
5x = 25
x = 25 : 5
x = 5