1)6x-1=2x-9 2)(7--2)=12 3)x/3+x/2=15

1)
6x-1=2x-9
6х - 2х = -9 + 1
4х = -8
х = -8/4 = -2 

2)
(7-4x)-(3x-2)=12
7 - 4x - 3x+2 = 12
-7х = 12 - 7 - 2
-7х = 3
7х = -3
х = -3/7

3)
x/3+x/2=15  |*6
2x + 3x = 90
5x = 90
x = 90/5 = 18

1) 6x-1=2x-9
6x-2x=-9+1
4x=-8
x=-2
2) (7-4x)-(3x-2)=12
7-4x-3x+2=12
9-4x-3x=12
9-7x=12
-7x=12-9
-7x=3
x=-3/7
3) x/3+x/2=15
2x/6+3x/6=15
5x/6=15
5x/6=15/1
5x=90
x=18