20%+(1-20%)(320-x)=320×40%
0.2+0.8(320-x)=128
0.2+256-0.8x=128
0.8x=0.2+256-128=128.2
x=128.2÷0.8
x=160.25
2(x-2)-3(4x-1)=9(1-x)
2x-4-12x+3=9-9x
12x-2x-9x=-4+3-6
x=-7
(x-1)-(3x+2)=-(x-1)
x-1-3x-2=-x+2
3x-x-x=-1-2-2
x=-5
1/2(1/2x-1)-1=1
1/2(1/2x-1)=2
1/2x-1=4
1/2x=5
x=10
1-3(8-x)=-2(15-2x)
1-24+3x=-30+4x
4x-3x=-1-24+30
x=7
1/5x-1/2(3-2x)=1
1/5x-3/2+x=1
6/5x=1+3/2=5/2
x=5/2÷6/5
x=25/12
-x=2/5x+1
x+2/5x=-1
7/5x=-1
x=-1÷7/5
x=-5/7