6x^2-x-1=0x^2-1/6x=1/6x^2-1/6x+1/144=1/6+1/144(x-1/12)^2=25/144x-1/12=±5/12x1=1/2，x2=-1/3
6x²-x-1=0(3x+1)(2x-1)=0x=-1/3,x=1/2
