1/2X-1=1/4X-1/2解:1/2X=1/4X-1/2+11/2X=1/4X+1/21/2X-1/4X=1/21/4X=1/2X=1/2÷1/4X=2
2/1x-1=4/1x-2/12/1x-4/1x=1+2/1-2/1x=3/13x=-2x=-2/3
2/1x-4/1x=-2/1+12/1x=2/1x=1