Question

先化简再求值： x²-2x+1/x²-1÷(1+ x-3/x+1),x=2008-5√3

Answer 1

原式=[(x-1)^2/(x+1)*(x-1)]÷[1+(x-3/x+1)]
=[(x-1)/(x+1)]÷[(x+1+x-3)/(x+1)]
=[(x-1)/(x+1)]÷[2(x-1)/(x+1)]
=[(x-1)/(x+1)]×[(x+1)/2(x-1)]
=1/2
——可见它与x的取值无关。

Answer 2

您好：

x²-2x+1/x²-1÷(1+ x-3/x+1)
=(x-1)²/(x-1)(x+1)÷(x+1+x-3)/(x+1)
=(x-1)÷(2x-2)
=1/2

如果本题有什么不明白可以追问，如果满意请点击“选为满意答案”
如果有其他问题请采纳本题后另发点击向我求助，答题不易，请谅解，谢谢。
祝学习进步！