x^2-3x+1=0x^2+1=3xx+1/x=3x^3+1/x^3=(x+1/x)(x^2-1+1/x^2)=(x+1/x)[(x+1/x)²-3]=3×(3²-1)=24
x^2-3x+1=0,x-3+1/x=0 (因为x不等于0,两边同时除以x) x+1/x=3 (x+1/x)^2=9 x^2+1/x^2+2=9 x^2+1/x^2=7 x^3+1/x^3=(x+1/x)(x^2+1/x^2-1)=3*(7-1)=18打酱油