把多项式1-x²+2xy-y²分解因式的结果是( ) A、(1-x-y)(1+x-y)A、(1-x-y)(1+x-y) B、(1+x-y)(1-x+y) C、(1-x-y)(1-x+y) D、(1+x-y)(1+x+y)
问题描述:
把多项式1-x²+2xy-y²分解因式的结果是( ) A、(1-x-y)(1+x-y)
A、(1-x-y)(1+x-y) B、(1+x-y)(1-x+y) C、(1-x-y)(1-x+y) D、(1+x-y)(1+x+y)
答
答案是B
答
1-x²+2xy-y²
=1-(x-y)^2
=(1+x-y)(1-x+y)
B
答
=1-(x-y)²
=(1+x-y)(1-x+y)
选B
答
B、(1+x-y)(1-x+y)