2x - 9 = 1
2x = 1 + 9
2x = 10 / : 2
x = 5
7x - 5 = 6x + 4
7x - 6x = 4 + 5
x = 9
-(x - 2) + 3(x - 1) = 2
-x + 2 + 3x - 3 = 2
-x + 3x = 2 - 2 + 3
2x = 3 / : 2
x = 1,5
9x + 3 = 7(x - 2) - 15
9x + 3 = 7x - 14 - 15
9x - 7x = -14 - 15 - 3
2x = -32 / : 2
x = -16
