## Intermediate Algebra (6th Edition)

$(x-1-z)(x-1+z)$
Using $a^2-b^2=(a+b)(a-b)$ or the factoring of the difference of two squares, then, \begin{array}{l} (x-1)^2-z^2 \\= [(x-1)-z][(x-1)+z] \\= (x-1-z)(x-1+z) .\end{array}