First problem.
3a - 4 <= 5
Add 4 to both sides.
3a <= 9
Divide both sides by 3.
3a/3 <= 9/3
a <= 3
Second problem.
n/(-3) + 5 > 4
Subtract 5 from both sides
n/(-3) > -1
Multiply both sides by -3.
When you multiply or divide both sides of an inequality by a negative number, the inequality sign switches direction.
n/(-3) * (-3) < -1 * (-3)
n < 3
