1. Решите уравнения: 1) 9x - 8 = 4x + 12; 2) 9 - 7(x + 3) = 5 - 4x.

Решение:

1. Уравнение 1:
   \( 9x - 8 = 4x + 12 \)
   \( 9x - 4x = 12 + 8 \)
   \( 5x = 20 \)
   \( x = \frac{20}{5} \)
   \( x = 4 \)
2. Уравнение 2:
   \( 9 - 7(x + 3) = 5 - 4x \)
   \( 9 - 7x - 21 = 5 - 4x \)
   \( -12 - 7x = 5 - 4x \)
   \( -7x + 4x = 5 + 12 \)
   \( -3x = 17 \)
   \( x = -\frac{17}{3} \)

Ответ: 1) \( x = 4 \); 2) \( x = -\frac{17}{3} \).