解方程；x/0.5-10+2=0 4(0.9-x)=3.2x 6.4-2(x+1.2)=0.4

1.x/0.5-10+2=0
x/0.5=8
x=4
2.4(0.9-x)=3.2x
3.6-4x=3.2x
3.6=7.2x
x=0.5
3.6.4-2(x+1.2)=0.4
6.4-2x-2.4=0.4
2x=3.6
x=1.8