3.4x-4=4.8-x 2x+7=x+5.5 5-3x=2x-8 9.5x+2=5.7x-5.6 1.5x+8=3.1x+16 2.9x+7.4=x+1.7

1) 3.4x - 4 = 4.8 - x,

3.4x + x = 4.8 +4,

4.4x  = 8.8,

x = 8.8 : 4.4,

x = 2.

Проверка: 3.4 *2 - 4 = 4.8 - 2,

6.8 - 4 = 2.8, 

2.8 = 2.8. 

2) 2x + 7 = x + 5.5,

2x - x = 5.5 - 7,

x = - 1.5.

Проверка: 2 * (-1.5) + 7 =- 1.5 + 5.5,

-3 + 7 = 4,

4 = 4.

3) 5 - 3x = 2x - 8,

5 +8  = 2x + 3x,

13 = 5x,

x =13 : 5,

x =2.6.

Проверка: 5 - 3 * 2.6 = 2 *2.6 - 8, 

5 - 7.8 = 5.2 - 8,   

- 2.8 = - 2.8. 

4) 9.5x + 2 = 5.7x - 5.6,

9.5x - 5.7x = - 5.6 - 2,

3.8x = - 7.6,

x = - 7.6 : 3.8,

x = - 2.

Проверка: 9.5 * (- 2) + 2 = 5.7 * (-2) - 5.6,

-19 + 2 =-11.4 - 5.6,

-17 =-17.

5)1.5x + 8 = 3.1x + 16,

3.1x -1.5x  = 8  - 16,

1.6x  = - 8,

x  = - 8 : 1.6,

x  = - 5.

Проверка: 1.5 * (- 5) + 8 = 3.1 * (- 5) + 16,

-7.5 + 8 = - 15.5 + 16,

0.5 = 0.5.

6) 2.9x + 7.4 = x + 1.7,

2.9x - x = 1.7 - 7.4,

1.9x = - 5.7,

x = - 5.7 : 1.9,

x = -3.

Проверка: 2.9 * (- 3) + 7.4 = -3 + 1.7,

 2.9 * (- 3) + 7.4 = -3 + 1.7,

- 8.7 + 7.4 = - 1.3,

- 1.3 = - 1.3.