2x-3=5x+7+9x
9x+5x-2x=-3-7
12x=-10
x=-5/6
3-6(x+2/3）=2/3
3-6x-4=2/3
6x=3-4-2/3=-5/3
x=-5/18
3/4x-0.4=1/2x+0.3
3/4x-1/2x=0.3+0.4
1/4x=0.7
x=2.8
(x+8)/3=-x
x+8=-3x
4x=-8
x=-2