Найдите корень уравнения: 1) 9 (x-1) = x+15 3) 12-4 (x-3) = 39-9x 2) (11x+14) - (5x-8) = 25 4) 2 (3x+5) - 3 (4x-1) = 11,8

Решаем линейные уравнения, используя тождественные преобразования.

1) 9 (x - 1) = x + 15;

9x - 9 = x + 15;

9x - x = 15 + 9;

8x = 24;

x = 24 : 8;

x = 3.

2) (11x + 14) - (5x - 8) = 25;

11x + 14 - 5x + 8 = 25;

11x - 5x = 25 - 14 - 8;

6x = 3;

x = 3 : 6;

x = 1/2.

3) 12 - 4 (x - 3) = 39 - 9x;

12 - 4x + 12 = 39 - 9x;

-4x + 9x = 39 - 12 - 12;

5x = 15;

x = 15 : 5;

x = 3.

4) 2 (3x + 5) - 3 (4x - 1) = 11,8;

6x + 10 - 12x + 3 = 11.8;

6x - 12x = 11.8 - 10 - 3;

-6x = - 1.2;

x = - 1.2 : (-6);

x = 0.2.

Ответ: 1) 3; 2) 1/2; 3) 3; 4) 0,2