459) (14 - x) * 4 - 8 = 20

Решение:

1. \( (14 - x) \cdot 4 - 8 = 20 \)
2. \( (14 - x) \cdot 4 = 20 + 8 \)
3. \( (14 - x) \cdot 4 = 28 \)
4. \( 14 - x = \frac{28}{4} \)
5. \( 14 - x = 7 \)
6. \( x = 14 - 7 \)
7. \( x = 7 \)

Ответ: x = 7.