4x - 5 = -3x - 4
4x + 3x = -4 +5
7x = 1
x = 1/7
3x + 1 = 9 + 5x
3x - 5x = 9 - 1
-2x = 8
x = 8/(-2) = -4
6x - 9 = 10x + 11
6x - 10x = 11 + 9
-4x = 20
x = 20/(-4) = -5
1 - 6x = -3/2x + 7
-6x + 3/2x = 7 - 1
-12/2x + 3/2x = 6
-9/2x = 6
x = 6*2/9 = 12/9 = 4/3
3x + 5 = x + 7
3x - x = 7 - 5
2x = 2
x = 1