（x-2x+1）(x-2x-1)

(x²－2x-1)(x²+2x-1) 分解因式，要过程

(x²－2x-1)(x²+2x-1) =[(x-1)²－2]×[(x+1)²－2] =(x-1+√2﹚﹙x-1-√2﹚﹙x+1+√2﹚﹙x+1-√2﹚ a（a－1）－（a²－b）＝﹣2 a²-a-a²+b=-2 a-b=2 ﹙a²＋b²﹚÷2－ab =(a²-2ab+b²)÷2 =(a-b)²÷2 =2²÷2 =2

(2X-1)*(X-1)等于几？

乘法分配律 原式=2X(X-1)-1×(X-1) =2X²-2X-X+1 =2X²-3X+1