x-0.2x-(0.2x+4)=x/3
0.8x-0.2x-4=x/3
0.6x-x/3=4
(1.8-1)x/3=4
0.8x=12
x=12/0.8
x=3/0.2
x=15
X-20%X-6-（20%X+6-2）=三分之一X
x-0.2x-6-(0.2x+6-2)=x/3
0.8x-6-(0.2x+4)=x/3
0.8x-6-0.2x-4=x/3
0.8x-0.2x-6-4=x/3
0.6x-10=x/3
(0.6-1/3)x=10
(1.8-1)x/3=10
0.8x=30
x=30/0.8
x=15/0.4
x=37.5