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先化简(x+1/x^2-x-x/x^2-2x+1)/x分之1,再选择一个恰当的x值代入求值,
题目详情
先化简(x+1/x^2-x-x/x^2-2x+1)/x分之1,再选择一个恰当的x值代入求值,
▼优质解答
答案和解析
(x+1/x^2-x-x/x^2-2x+1)/x分之1
=(x+1/x(x-1)-x/(x-1)²)x
=(x+1)/(x-1)-x²/(x-1)²
={(x+1)(x-1)-x²}/(x-1)²
=(x²-1-x²)/(x-1)²
=-1/(x-1)² (取x=2）
=-1/（2-1）²
=-1
=(x+1/x(x-1)-x/(x-1)²)x
=(x+1)/(x-1)-x²/(x-1)²
={(x+1)(x-1)-x²}/(x-1)²
=(x²-1-x²)/(x-1)²
=-1/(x-1)² (取x=2）
=-1/（2-1）²
=-1
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