To solve these equations:

1) 69 - x = 43
Subtract 69 from both sides:
-x = -26
Divide by -1 to solve for x:
x = 26

2) x - 21 = 42
Add 21 to both sides:
x = 63

3) 28 + x = 59
Subtract 28 from both sides:
x = 31

4) 56 - x = 43
Subtract 56 from both sides:
-x = -13
Divide by -1 to solve for x:
x = 13

5) x - 15 = 25
Add 15 to both sides:
x = 40

Therefore, the solutions are:
1) x = 26
2) x = 63
3) x = 31
4) x = 13
5) x = 40