把多项式(1+x)(1-x)-(x-1)提取公因式(x-1)后,余下的因式是( ) A.(x+1) B.-(x+2) C.-(x+1) D.x
问题描述:
把多项式(1+x)(1-x)-(x-1)提取公因式(x-1)后,余下的因式是( )
A. (x+1)
B. -(x+2)
C. -(x+1)
D. x
答
(1+x)(1-x)-(x-1),
=-(1+x)(x-1)-(x-1),
=(x-1)(-1-x-1),
=(x-1)(-2-x),
=-(x-1)(x+2),
故选:B.