Question

(–x-1)(1-x)等于多少？

Answer 1

解: (-x-1)(1-x)
=[-(x+1)][-(x-1)]
=(x+1)(x-1)
=x²-1

Answer 2

将两个因式进行乘法展开，得到：

(–x-1)(1-x) = –x - x^2 - 1 + x

将同类项合并，得到：

(–x-1)(1-x) = -x^2 - 1

因此，(–x-1)(1-x)等于-x^2-1。