А) 2х=18-х : б)7х+3=30-2х : в)7-2х=3х-18 : г)3(х-2)=х+2 : д)5-2 (х-1)=4-х ; е)(7х++3)=5 : к\р умру если 2 получу !

а) 2х = 18 - х

2х + x = 18

3x = 18

x = 18 : 3

x = 6

б) 7x + 3 = 30 - 2x

7x + 2x = 30 - 3

9x = 27

x = 27 : 9

x = 3

в) 7 - 2x = 3x - 18

- 2x - 3x = -18 - 7

-5x = -25

5x = 25

x = 5

г) 3(x - 2) = x + 2

3x - 6 = x + 2

3x - x = 2 + 6

2x = 8

x = 4

д) 5 - 2(x - 1) = 4 - x

5 - 2x + 2 = 4 - x

-2x + x = 4 - 2 - 5

-x = -3

x = 3

е) (7х + 11) - (9х + 3) = 5 :

7x + 11 - 9x - 3 = 5

7x - 9x = 5 + 3 - 11

-2x = -3

2x = 3

x = 1.5

а) 2·x=18-x

2·x+x = 18

3·x = 18

x=18:3

x = 6

Проверка:

2·6=18-6

12=12 верно!

б) 7·x+3=30-2·x

7·x+2·x = 30-3

9·x = 27

x = 27:9

x=3

Проверка:

7·3+3=30-2·3

21+3=30-6

24=24 верно!

в) 7-2·x=3·x-18

-2·x-3·x = -18-7

-5·x = -25

x = -25:(-5)

x = 5  

Проверка:

7-2·5=3·5-18

7-10=15-18

-3 = -3 верно!

г) 3·(x-2)=x+2

3·x-6 = x+2

3·x-x = 2+6

2·x = 8

x = 8:2

x = 4

Проверка:

3·(4-2)=4+2

3·2=6

6 = 6 верно!

д) 5-2·(x-1)=4-x

5-2·x+2=4-x

-2·x+x=4-5-2

-x=-3

x=3

Проверка:

5-2·(3-1)=4-3

5-2·2=1

5-4=1

1 = 1 верно!

е) (7·x+11)-(9·x+3)=5

7·x+11-9·x-3 = 5

-2·x = 5+3-11

-2·x = -3

x = -3:(-2)

x = 1,5

Проверка:

(7·1,5+11)-(9·1,5+3)=5

(10,5+11)-(13,5+3)=5

21,5-16,5=5

5 = 5 верно!