Since xyz=1,
x+y1⟺1−y=−z(1−y2)⟺y=1 or z=−1+y1=y+z1⟺xyz+z=y2z+y
If y=1, the system reduces to xz=1⟺z=x1 and
x+1=1+z1=z+x1⟺x+1=1+x=x2⟺x=1 or x=−2
If z=−1+y1, then xyz=1⟺x=−y1+y and
−y1+y+y1=y−(1+y)=−1+y1−1+yy
(Solutions)
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which is true for every y=0,−1 (all three expressions are equal to −1).
So all solutions are (1,1,1) and (−t1+t,t,−1+t1) and its cyclic analogous triples. Notice that t=1 yields the solution (−2,1,−21).