3х=28-х 5х+12=8х+30 33+8х=-5х+72

3х = 28 - х; 5х + 12 = 8х + 30; 33 + 8х = -5х + 72;Решим уравнения:1. 3x = 28 - x3x - x = 282x = 28x = 14;2. 5x +12 = 8x + 305x - 8x = 30 - 12-3x = 18x = - 6;3. 33 + 8x = -5x + 728x - 5x = 72 - 3313x = 39x = 3;Ответ: 1. x = 14; 2. x = -6; 3. x = 3;