Ответ:

1. k : 16 – 109 = 231

k : 16 = 231+109

k : 16 = 340

k = 5440

2. 8 · (х - 7) = 1080

8x - 56 = 1080

8x = 1080+56

8x = 1136

x = 142

3. (k + 11) : 23 = 27

k + 11 = 27*23

k + 11 = 621

k = 621 - 11

k = 610

4. 900 : (210 +х) = 36

210 + x = 900 : 36

210 + x = 25

x = 25 - 210

x = -185

5. 40 + х : 70 = 54

x : 70 = 54 - 40

x : 70 = 14

x = 980

6. 142 - (123 - х) + 14 =111

142 - 123 + x + 14 = 111

x = 111 - 142 + 123 - 14

x = 78

7. 67 – 36 : х = 55

36 : x = 55-67

36 : x = -12

x = 36 : (-12)

x = -3

8. 24 : (х +2) = 60 : 15

x + 2 = 24/4

x + 2 = 6

x = 6 - 2

x = 4

9. 17 + 6·(х - 5) = 47

17 + 6x - 30 = 47

6x = 47 - 17 + 30

6x = 60

x = 10

10. 40 - 3 · (х + 2) = 10

40 - 3x - 6 = 10

-3x = 10 - 40 + 6

-3x = -24

x = 8

11. 2 · (х - 12) +19 = 19

2x - 24 + 19 = 19

2x = 19+24-19

2x = 24

x = 12

12. 63 : (2х - 1) = 21 : 3

2x - 1 = 63 : 7

2x - 1 = 9

2x = 9+1

2x = 10

x = 5

13. 248 : (41 - 2х) = 8

41 - 2x = 248 : 8

41 - 2x = 31

-2x = 31 - 41

-2x = -10

x = 5

14. 18 · (7х + 26) = 1854

126x + 468 = 1854

126x = 1854 - 468

126x = 1386

x = 11

15. 336 : (5х + 1) = 6

5x + 1 = 336 : 6

5x + 1 = 56

5x = 56-1

5x = 55

x = 11

16. 21· (5х+14)=2499

105x + 294 = 2499

105x = 2499 - 294

105x = 2205

x = 21

17. 6x + 131 = 437

6x = 437 - 131

6x = 306

x = 51

18. 238 + х : 8 = 265

x : 8 = 265 - 238

x : 8 = 27

x = 216

19. 490 - 7y = 350

-7y = 350 - 490

-7y = -140

y = 20

20. 9x – 754 = 155

9x = 155 + 754

9x = 909

x = 101

21. 8 · (х - 7) = 1080

8x - 56 = 1080

8x = 1080 + 56

8x = 1136

x = 142

22. 124 : (3х +4) = 4

3x + 4 = 124 : 4

3x + 4 = 31

3x = 31 - 4

3x = 27

x = 9

23. (5х+1) : 16 =6

5x + 1 = 6*16

5x + 1 = 96

5x = 96 - 1

5x = 95

x = 19

24. (483-8х) : 43 = 9

483 - 8x = 43*9

483 - 8x = 387

-8x = 387 - 483

-8x = -96

x = 12