题目已知xxx,yyy为实数,且y=x−1+1−x−2y=\sqrt{x-1}+\sqrt{1-x}-2y=x−1+1−x−2.(1)(1)(1)确定xxx、yyy的值；(2)(2)(2)求代数式(2x−y)(x+y)−(x+y)(x−y)\left(2x-y\right)\left(x+y\right)-\left(x+y\right)\left(x-y\right)(2x−y)(x+y)−(x+y)(x−y)的值.知识点：分式的化简求值章节：数与式 / 分式
