Which of these is a homogeneous system?
x+y=0,x−y=0x+y=0, x-y=0x+y=0,x−y=0
x+y=1,x−y=0x+y=1, x-y=0x+y=1,x−y=0
x=0,y=1x=0, y=1x=0,y=1
x+y+z=0x+y+z=0x+y+z=0