X/X2-3X+1=1
1/X-3X+1=1
1-3X2=0
X2=1/3
X=正负3分之根号3
原式=3-3+1=1第二步怎么来的？把X2=1/3带入原式=3-3+1=1x/(x2-3x+1)=1,那x2/(x4-9x2+1)=?x/(x2-3x+1)=1解得X2-4X+1=0X=2加减根号3X2=4X-1x2/(x4-9x2+1)=（4X-1）/（16X2-44X+11）将X带入得