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先化简再求值x+2分之1-x+2分之x的平方+2x+1除以x-1分之x的平方-1其中x=根号2-2

题目详情
先化简再求值x+2分之1-x+2分之x的平方+2x+1除以x-1分之x的平方-1其中x=根号2-2
▼优质解答
答案和解析
原式=[1/(x+2)]-[(x+2x+1)/(x+2)]÷[(x-1)/(x-1)] =[1/(x+2)]-[(x+1)/(x+2)]÷[(x+1)(x-1)/(x-1)] =[1/(x+2)]-[(x+1)/(x+2)]÷(x+1) =[1/(x+2)]-[(x+1)/(x+2)]×[1/(x+1)] =[1/(x+2)]-[(x+1)/(x+2)] =(1-x-1)/(x+2) =-x/(x+2) 当x=√2-2时 原式=-(√2-2)/(√2-2+2) =(2-√2)/√2 =√2(2-√2)/2 =(2√2-2)/2 =√2-1