3(x - 7) = 9

Решение:

1. \( 3(x - 7) = 9 \)
2. \( x - 7 = \frac{9}{3} \)
3. \( x - 7 = 3 \)
4. \( x = 3 + 7 \)
5. \( x = 10 \)

Ответ: 10