I'm going to be honest and say i suck at math. if you can that will be amazing.

24) 3x - 4 - x = 12

2x - 4 = 12
2x = 12 + 4
2x = 16
x = 8

Option D.

25) 2x + 3 = 3(x + 2)

2x + 3 = 3x + 6
3 - 6 = 3x - 2x
- 3 = x

Option D again.

26) 


m = 2.8(-7.11 + 4.9)
m = - 6.188

None of your options are correct, though I'm willing to bet that option C is supposed to be this selection.

27) - 11 ≥ 6 - 2n - 5

- 11 ≥ - 2n + 1
- 12 ≥ - 2n
6 ≤ n so n ≥ 6

Closed circle on 6, arrow should go to the right. Option C

28) - 11 = 6 - 2n - 5

Same as above. n = 6. None of those are correct again (your teacher needs to pay attention to their worksheets). Option A or Option C, I guess. 

29) - 2x ≥ 4(x + 3)

- 2x ≥ 4x + 12
- 2x - 4x ≥ 12
- 6x ≥ 12
x ≤ - 2

Option B