1)
9( x - 1) = x + 15
9x-9=x+15
9x-x=15+9
8x=24
x=24:8
x=3
----
2)
(11x + 14) - (5x - 8) = 25
11x+14-5x+8=25
6x+22=25
6x=25-22
6x=3
x=3:6
x=0,5
------
3)
12 - 4( x - 3 ) = 39 - 9x
12-4x+12=39-9x
24-4x=39-9x
-4x+9x=39-24
5x=15
x=15:5
x=3
-----
4)
2( 3x + 5 ) - 3(4x - 1 ) = 11,8
6x+10-12x+3=11,8
-6x+13=11,8
6x=13-11,8
6x=1,2
x=1,2:6
x=0,2