1.8*(x+1/5）=3.2
1.8*x+1.8*1/5=3.2
1.8x=3.2-0.36
x=2.84/1.8=约1.578
y-1/5y=5.6
4/5y=5.6
y=7
3/5*(x-50%）=1/10
3/5*x-3/5*50%=1/10
3/5*x=1/10+0.3
x=0.4/0.6=2/3
30%x-3/5=12/5
30%x=12/5+3/5=3
x=3/30%=10
4*（x-0.5)=4/5
4*x-4*0.5=4/5
4x=4/5+2
x=0.7
1/4*(x-0.75)=13/16
1/4*x-1/4*0.75=13/16
1/4*x=13/16+3/16=1
x=4
20%x=3/5-x
20%x+x=3/5
1.2x=3/5
x=0.5