1/4x-1/2=3/4x-2=3x=51/2x-7=9x-2/63x-42=9x-26x=-40x=-20/31/5x-1/2(3-2x)=12x-5(3-2x)=102x-15+10x=10缉抚光幌叱呵癸童含阔12x=25x=25/12