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

(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.