12-0.3(x-0.1)=1.2
120-3(x-0.1)=12
40-(x-0.1)=4
40-x+0.1=4
40.1-x=4
x=40.1-4
x=36.1
4（2+x）÷2=22
2（2+x）=22
（2+x）=11
x=11-2
x=9