（1） 2x²-4x+1=0x²-2x+1/2=0x²-2x+1-1+1/2=0(x-1)²=1/2x-1=±√2/2x=1±√2/2(2)2y²-7y+3=0(y-3)(2y-1)=0y-3=0 或 2y-1=0,即 y=3 或 y=1/2(3) 2x²-12x+7=0x²-12x+36-36+7=0(x-6...