设2分之X=3分之y=4分之Z=k则:x=2k;y=3k;z=4kX+Y+Z=9则:2k+3k+4k=99k=9k=1所以:X+Y一Z=2k+3k-4k=k=1
令x/2=y/3=z/4=k,则x=2k,y=3k,z=4kx+y+z=92k+3k+4k=99k=9k=1x=2k=2 y=3k=3 z=4k=4 x+y-z=2+3-4=1
假设:2分之X=3分之y=4分之Z=1 求出X=2,y =3Z=4,满足X+Y+Z=9,所以X+Y一Z=1