Ответ:

Пошаговое объяснение:

2x = 18 - x

2x + x = 18

3x = 18

x = 18:3

x = 6

-------------

7x + 3 = 30 - 2x

7x + 2x = 30 - 3

9x = 27

x = 27:9

x = 3

---------------

7 - 2x = 3x - 18

3x + 2x = 7 + 18

5x = 25

x = 25:5

x = 5

---------------

5 - 2(x - 1) = 4 - x

5 - 2x + 2 = 4 - x

7 - 2x = 4 - x

2x - x = 7 - 4

x = 3

-----------------

(7x + 1) - (9x + 3) = 5

7x + 1 - 9x - 3 = 5

-2x - 2 = 5

-2x = 5+2

-2x = 7

x = -7:2

x = -3,5

------------------

3/8 x + 15 = 1/6 x + 10   |*24

9x + 360 = 4x + 240

9x - 4x = 240 - 360

5x = -120

x = -120:5

x = -24

--------------------------

4(5x + 2) = 10(2x - 3) + 15

20x + 8 = 20x - 30 + 15

20x + 8  = 20x - 15

20x - 20x = -15 - 8

0 ≠ -23

нет решений

--------------------------

2(7x - 7) = 7(2x - 3) + 7

14x - 14 = 14x - 21 + 7

14x - 14 = 14x - 14

14x - 14x = 14 - 14

0 = 0

x є (-∞ ; ∞)

уравнение имеет множество решений