1144. Чему равен корень уравнения:

1) 3x = 28 - x => 4x = 28 => x = 7

2) 5x + 12 = 8x + 30 => -3x = 18 => x = -6

3) 33 + 8x = -5x + 72 => 13x = 39 => x = 3