Which of these systems is homogeneous?
x+y=1x+y=1x+y=1
2x+3y=02x+3y=02x+3y=0
x+y=z,x−y=1x+y=z, x-y=1x+y=z,x−y=1
x+y=z+1x+y=z+1x+y=z+1