先化简再求值1/x+2-x²+2x+1/x+2÷x²-1/x-1,其中x=根号2-2
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1/(x+2) - (x²+2x+1)/(x+2) ÷(x²-1)/(x-1)
=1/(x+2) - (x+1)²/(x+2) ÷ (x+1)
=1/(x+2) - (x+1)/(x+2)
=(1-x-1)/(x+2)
=-x/(x+2)
=-(根号2 -2)/(根号2-2+2）
=（2-根号2)/根号2
=根号2 -1
=1/(x+2) - (x+1)²/(x+2) ÷ (x+1)
=1/(x+2) - (x+1)/(x+2)
=(1-x-1)/(x+2)
=-x/(x+2)
=-(根号2 -2)/(根号2-2+2）
=（2-根号2)/根号2
=根号2 -1
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