Answer: [tex]\Large \boldsymbol{} (x-y-z+1)(x+y-z-1)[/tex]
Step-by-step explanation:
[tex]\Large \boldsymbol{} 1) \ {(a-b)^2=a^2+2ab+b^2 } \\\\2) \ {a^2-b^2=(a-b)(a+b)} \\\\\\ x^2-y^2+z^2-2xz+2y-1= \\\\\underbrace{x^2-2xz+z^2}_{(x-z)^2} -\underbrace{(y^2-2y+1)}_{(y-1)^2}= \\\\\\ (x-z)^2-(y-1)^2 =(x-y-z+1)(x+y-z-1)[/tex]
