Hello,
5x + 7 = 2x - 2
5x - 2x = - 2 - 7
3x = -9
x = -9/3 = -3
3x + 2 = x - 10
3x - x = - 10 - 2
2x = -12
x = -12/2 = -6
21 - 5 = 5x + 1
5x + 1 = 16
5x = 16 - 1
5x = 15
x = 15/5 = 3
3 - 7x = 3x + 2
- 7x - 3x = 2 - 3
-10x = -1
x = 1/10
5x - 6 = -x + 3
5x + x = 3 + 6
6x = 9
x = 9/6 = 3/2 = 1.5
2x - 1 = 1
2x = 1 + 1
2x = 2
x = 2/2 = 1