Ответ:

Принцип решения понятен, я думаю, с остальным сама должна справиться

Пошаговое объяснение:

Желаю удачи

1) 15x + 10 = 6x – 8

15x – 6x = –8 – 10

9x = –18

x = –18 / 9 = –2

2) –2(x – 4) = 3 + 7x

–2x + 8 = 3 + 7x

7x + 2x = 8 – 3

9x = 5

x = 5/9

3) 26x – 6 = 8x – 42

26x – 8x = 6 – 42

18x = –36

x = –36 / 18 = –2

4) 10x – 8 = 20x + 74

20x – 10 x = –8 – 74

10x = –82

x = –82 / 10 = –8,2

5) 13x + 8 = 27x + 18

27x – 13x = 8 – 18

14x = –10

x = –10 / 14 = –5/7

6) 1,2(x – 4) + 4,6 = 0,3(3 + x)

1,2x – 4,8 + 4,6 = 0,9 + 0,3x

1,2x – 0,3x = 0,9 + 4,8 – 4,6

0,9x = 1,1

x = 1,1 / 0,9 = 11/9

7) –0,6(x – 3) – 3,3 = 0,6(4 – x)

–0,6x + 1,8 – 3,3 = 2,4 – 0,6x

–0,6x + 0,6x = 2,4 – 1,8 + 3,3

0 = 3,9

Решений нет

8) (x – 3) / (x + 5) = 5 / 8 ⇒ ОДЗ: x ≠ –5

8(x – 3) = 5(x + 5)

8x – 24 = 5x + 25

8x – 5x = 25 + 24

3x = 49

x = 49/3

9) (x – 3) / 5 = (x + 8) / 4

4(x – 3) = 5(x + 8)

4x – 12 = 5x + 40

5x – 4x = –12 – 40

x = –52

10) 7 / (x + 8) = 6 / (2 – x) ⇒ ОДЗ: x ≠ –8, x ≠ 2

7(2 – x) = 6(x + 8)

14 – 7x = 6x + 48

6x + 7x = 14 – 48

13x = –34

x = –34/13

11) (9y – 2)(2,1 – 7y) = 0

9y – 2 = 0 ⇒ 9y = 2 ⇒ y = 2/9

2,1 – 7y = 0 ⇒ 7y = 2,1 ⇒ y = 2,1/7 = 3/10

y₁ = 2/9, y₂ = 3/10

12) (–2x – 8,4)(0,7x + 4,2) = 0

–2x – 8,4 = 0 ⇒ 2x = –8,4 ⇒ x = –8,4 / 2 = –4,2

0,7x + 4,2 = 0 ⇒ 0,7x = –4,2 ⇒ x = –4,2 / 0,7 = –6

x₁ = –4,2, x₂ = –6