x²-y²-2y-1因式分解怎么做?

x²-y²-2y-1因式分解怎么做?
x²-y²-2y-1因式分解怎么做?

x²-y²-2y-1因式分解怎么做?
您好!
x^2-y^2-2y-1
=x^2-(y^2+2y+1)
=x^2-(y+1)^2
=(x+y+1)(x-y-1)
这里还是考察a^2-b^2=(a+b)(a-b)这个平方差公式,只是这里b是y+1这个式子
祝你学习进步O(∩_∩)O哈!