(1)-3x²+1=6x3x²-6x-1=03(x²-2x+1)-3-1=03(x-1)²=4(x-1)²=4/3x-1=±2√3/3x=1±2√3/3（2）x²-6x+9=5-2xx²-4x+4=0(x-2)²=0x1=x2=2（2）x²-6x+9=5-2xx²-4x+4=0(x-2)²=0x1=x2=2 写清楚过程(x-2)²=0x-2=0或x-2=0所以x1=x2=2