Simplify each rational expression. State any restrictions on the variable.
(x^2 - 2x - 24)/(x^2 + 7x + 12) * (z^2 - 1)/(x - 6)
[(x - 6)(x + 4)] / [(x + 4)(x + 3)] * (z - 1) / (x - 6)
Simplify:
= (x - 6)/(x + 3) * (z - 1)
Restriction: x ≠ -4, -3, 6 (to avoid division by zero)