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

1) 9x - 4x = 12 + 8 => 5x = 20 => x = 4.

2) 9 - 7x - 21 = 5 - 4x => -7x + 4x = 5 + 21 - 9 => -3x = 17 => x = -17/3.