2*(2*x)=1*x 就是
2/2-(2/2-x/3)/3=1/2-x/3
两端乘3:
3-(1-x/3)=3/2-x
2+x/3=3/2-x
两端乘6:
12+2x=9-6x
3+8x=0
x=-3/8