00:00:00
X - 30 = 20
- 50
X - 10 = 30
- 40
2X - 20 = 40
- 30
3X = X + 30
- 15
4X - 40 = 100
- 35
20X + 30X = 200
- 4
X - 100 = 200
- 300
5X + 7X = 120
- 10
2X + 4X = 60
- 10