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
11x-5x=25-14-8
6x=3
x=3/6
x=0.5
3.
12 - 4( x - 3 ) = 39 - 9x
12-(4x-12)=39-9x
12-4x+12=39-9x
-4x+9x=39-12-12
5x=15
x=15/5
x=3
4.
2( 3x + 5 ) - 3(4x - 1 ) = 11,8
6x+10-12x+3=11.8
6x-12x=11.8-10-3
-6x=-1.2
x=-1.2/(-6)
x=0.2