Решите уравнение: 1) 21x + 45 = 17 + 14x2) 13x + 70 = 2x + 15 3) 1,5x + 8 = 3,1x + 164) 2,9x + 7,4 = x + 1,75) 1,1 x - 2 целых 1/3 = 3/5x6) 6,75x = 2 целых 1/4x - 9

Найдем корни.

1) 21 * x + 45 = 17 + 14 * x;

Запишем уравнения в виде a * x = b.

21 * x - 14 * x = 17 - 45;

7 * x = - 30 + 2;

7 * x = - 28;

x = - 28/7;

x = - 4.

2) 13 * x + 70 = 2 * x + 15;

13 * x - 2 * x = 15 - 70;

11 * x = - 60 + 5;

11 * x = - 55;

x = - 55/11;

x = - 5.

3) 1,5 * x + 8 = 3,1 * x + 16;

1.5 * x - 3.1 * x = 16 - 8;

-2 * x + 0.4 * x = 8;

-1.6 * x = 8;

x = 8 / (-1.6);

x = - 80/16;

x = - 10/2;

x = - 5.

4) 2,9 * x + 7,4 = x + 1,7;

2.9 * x - x = 1.7 - 7.4;

1.9 * x = - 6 + 0.3;

1.9 * x = - 5.7;

19 * x = - 57;

x = - 57/19;

x = - 3.

5) 1,1 * x - 2 1/3 = 3/5 * x;

1.1 * x - 0.6 * x = 2 1/3;

0.5 * x = 2 1/3;

1/2 * x = 7/3;

3 * x = 14;

x = 14/3.

6) 6,75 * x = 2 1/4 * x - 9;

6.75 * x - 2.25 * x = - 9;

4.5 * x = - 9;

x = - 9/4.5;

x = - 90/45;

x = - 2.