解2x²-x-1=0x²-1/2x-1/2=0x²-1/2x+1/16=1/2+1/16(x-1/4)²=9/16∴x-1/4=3/4或x-1/4=-3/4∴x=1或x=-1/2(2x-1)²=x(3x+2)-74x²-4x+1=3x²+2x-7x²-6x=-8x²-6x+9=1(x-3)²...