Assume we have the following rules
(1) X + 0 ->> X
(2) M + N ->> P if P is M + N
(3) X * 0 ->> 0
(4) X * 1 ->> X
(5) M * N ->> P if P is M * N
(6) X = X ->> true
Which rules do you want to add to rewrite the term
(x * y) + z = z + (y * x)
to true?