Solve: x+y+z=0,x=y,y=zx + y + z = 0, x = y, y = zx+y+z=0,x=y,y=z.
(0,0,0)(0, 0, 0)(0,0,0)
(1,1,−2)(1, 1, -2)(1,1,−2)
Infinitely many
No solution