作业已知X/Y=3/2,求X
已知X/Y=3/2,求X-Y/X+Y的值
因为X/Y=3/2,所以2x=3y 即2x-3y=0 即2x-2y-y=0 2x-2y=y x-y=y/2 同理,由2x-3y=0得:2x+2y-2y-3y=0 2x+2y=5y x+y=5y/2 所以(X-Y)/(X+Y)=(y/2)/(5y/2)=1/5