x²-x-y²-y的因式分解

更新时间：2018-05-18 19:14:04 134次访问

解：原式=(x²-y²)-(x+y )    

              =(x+y)(x-y)-(x+y)    

              =(x+y)(x-y-1)

x²-x-y²-y

=x²-y²-x-y

=(x²-y²)-(x+y)

=(x+y)(x-y)-(x+y)

=(x+y)(x-y-1)

x²-x-y²-y=(x-y)(x+y)-x-y=（x+y)(x-y)-（x+y）=(x-y)(x+y-1)

X2-y2-（x+y）=（x+y）（x-y）-(x+y)=(x+y）（x-y-1）