公式法解方程1.2x²-4x=12.x²-3x=03.1/4x²-x+1=04.2x&su

1。2x²-4x=1x²-2x-1/2=0x²-2x+1-1-1/2=0（x-1）²=3/2x-1=±√6/2x1=1+√6/2x2=1-√6/22。x²-3x=0x²-3x+9/4-9/4=0（x-3/2）²=9/4x-3/2=±3/2x1=3,x2=03。1/4x²-x+1=0x²-4x+4=0（x-2）²=0x-2=0x=24。2x²=6x-52x²-6x+5=0x²-3x+5/2=0x²-3x+9/4-9/4+5/2=0（x-3/2)²=-1/4无解。