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