0.2分之0.1x+0.05-0.5分之0.2x-0.05+5/4=0
5(0.1x+0.05)-2(0.2x-0.05)+1.25=0
0.5x+0.25-0.4x+0.1+1.25=0
0.1x+1.6=0
0.1x=-1.6
x=-16