№3 Решите уравнение: 5(х – 3,6) = 9x. Решите уравнение: 18 – 5(9 – x) = 8. Решите уравнение: 2x – 3(3x + 1) = 11. Решите уравнение: 6x – 8 = 5x – 3(x – 4). Решите уравнение: 8 – 5(8 + 3x) = 13.

1) 5(x – 3,6) = 9x

5x – 18 = 9x

–18 = 9x – 5x

–18 = 4x

x = \(\frac{-18}{4}\)

x = -4,5

Ответ: x = -4,5

2) 18 – 5(9 – x) = 8

18 – 45 + 5x = 8

–27 + 5x = 8

5x = 8 + 27

5x = 35

x = \(\frac{35}{5}\)

x = 7

Ответ: x = 7

3) 2x – 3(3x + 1) = 11

2x – 9x – 3 = 11

–7x = 11 + 3

–7x = 14

x = \(\frac{14}{-7}\)

x = -2

Ответ: x = -2

4) 6x – 8 = 5x – 3(x – 4)

6x – 8 = 5x – 3x + 12

6x – 8 = 2x + 12

6x – 2x = 12 + 8

4x = 20

x = \(\frac{20}{4}\)

x = 5

Ответ: x = 5

5) 8 – 5(8 + 3x) = 13

8 – 40 – 15x = 13

–32 – 15x = 13

–15x = 13 + 32

–15x = 45

x = \(\frac{45}{-15}\)

x = -3

Ответ: x = -3