Ответ:

1. x+3=9

x=9-3

x=6

3. 6x+1=-4x

6x+4x=-1

10x=-1

x=-1/10

5. 3x+3=5x

-2x=-3

x=3/2

7. 7+8x=-2x-5

8x+2x=-5-7

10x=-12

x=-1,2

9. 1-10x=-5x+10

-10x+5x=10-1

-5x=9

x=-9/5

11. 2+3x=-7x-5

3x+7x=-5-2

10x=-7

x=-0,7

13. 4(x-8)=-5

4x-32=-5

4x=-5+32

4x=27

x=6,75

15. 5(x+9)=-8

5x+45=-8

5x=-8-45

5x=-53

x=-10,6

17. 10(x+2)=-7

10x+20=-7

10x=-7-20

10x=-27

x=-2,7

19. x+x/9=-10/3

9x+x=-30

10x=-30

x=-3

21. x+x/5=-12/5

5x+x=-12

6x=-12

x=-2

23. x+x/2=-9

2x+x=-18

3x=-18

x=-6