We have to solve the inequalities:
2.
x-7 > 10
Add 7 on both sides
x-7+7 > 10+7
x> 17
3.
3x≤21
Divide both sides by 3
3x/3 ≤ 21/3
3 ≤ 7
4.
5a- 2 < 18
Add both sides 2 units
5a - 2 +2 <18+2
5a <20
Divide both sides by 5
5a/5 < 20/5
a < 4
5.
2t + 8 ≥ -4(t+1)
2t + 8 ≥ -4*t + (-4*1)
2t + 8 ≥ -4t -4
Subtract both sides by 8
2t +8 -8 ≥ -4t -4 -8
2t ≥ -4t -12
Add 4t to both sides
2t + 4t ≥ -4t + 4t -12
6t ≥ -12
Divide both sides by 6
6t /6 ≥ -12/6
t ≥ -2