两边乘以4
2(0.1x+0.05)-8(0.2x-0.05)+5=0
0.2x+0.1-1.6x+0.4+5=0
1.6x-0.2x=0.1+0.4+5
1.4x=5.5
x=5.5÷1.4
x=55/14