问题
选择题
把x2-y2-2y-1分解因式结果正确的是( )。
A.(x+y+1)(x-y-1)
B.(x+y-1)(x-y-1)
C.(x+y-1)(x+y+1)
D.(x-y+1)(x+y+1)
答案
A.
题目分析:原式=x2-(y2+2y+1),
=x2-(y+1)2,
=(x+y+1)(x-y-1).
故选A.
把x2-y2-2y-1分解因式结果正确的是( )。
A.(x+y+1)(x-y-1)
B.(x+y-1)(x-y-1)
C.(x+y-1)(x+y+1)
D.(x-y+1)(x+y+1)
A.
题目分析:原式=x2-(y2+2y+1),
=x2-(y+1)2,
=(x+y+1)(x-y-1).
故选A.