4(x - 3) = 12

Решение:

1. \( 4(x - 3) = 12 \)
2. \( x - 3 = \frac{12}{4} \)
3. \( x - 3 = 3 \)
4. \( x = 3 + 3 \)
5. \( x = 6 \)

Ответ: 6