(1)x2-4x+1=0移项,x2-4x=-1配方,x2-4x+4=-1+4即(x-2)2=3解得,x1=2+ 3 ,x2=2? 3 ;(2)x2-5x-6=0分解因式得,(x-6)(x+1)=0x1=6,x2=-1.