题目 把x2−y2−2y−1{{x}^{2}}-{{y}^{2}}-2y-1x2−y2−2y−1分解因式，结果正确的是( ) A.(x+y+1)(x−y−1)(x+y+1)(x-y-1)(x+y+1)(x−y−1)B.(x+y−1)(x−y−1)(x+y-1)(x-y-1)(x+y−1)(x−y−1)C.(x+y−1)(x+y+1)(x+y-1)(x+y+1)(x+y−1)(x+y+1)D.(x−y+1)(x+y+1)(x-y+1)(x+y+1)(x−y+1)(x+y+1)知识点：分组分解法章节：第12章 因式分解 / 12.2 因式分解的方法
