Bonjour,
1.
x - 7 > 2
x > 2 + 7
x > 9
2.
x + 9 < 4
x < 4 - 9
x < - 5
3.
x + 8 ≤ - 2x + 5
x + 2x ≤ 5 - 8
3x ≤ - 3
x ≤ - 1
4.
13 > 8 + x
x < 13 - 8
x < 5
5.
- 3x ≥ 7
x ≤ - 7/3