90+12x=150 32-4x=16 5*（4x+7）=75 5.9X-9=4.2x=2.9 6(3x-2)-4(4x-3)=1 7/9X-1/3=1/3X+1/4

90+12x=150
12x=60
x=5
32-4x=16
4x=16
x=4
5*（4x+7）=75
4x+7=15
4x=8
x=2
5.9X-9=4.2x+2.9
1.7x=11.9
x=7
6(3x-2)-4(4x-3)=1
18x-12-16x+12=1
2x=1
x=0.5
7/9X-1/3=1/3X+1/4
4/9x=7/12
x=7/16