暖意序言 2 2025-02-14 21:41 (x⁴-2+x⁻⁴)+(x²-2+x⁻²)=0,(x²-x⁻²)²+(x-x⁻¹)²=0,(x+x⁻¹)²(x-x⁻¹)²+(x-x⁻¹)²=0,(x-x⁻¹)²[(x+x⁻¹)²+1]=0,∵(x+x⁻¹)²+1≠0,∴x-x-1=0,x²-1=0,x=±1
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