2x²-3x+1=0x²-3/2x+1/2=0x²-3/2x+1/2+9/16-9/16=0(x-3/4) ²=1/16x-3/4=±1/4x1=1x2=1/2
利用十字相乘法!2x²-3x+1=0(2x-1)(x-1)=0x=1/2或x=1十字相乘的应用:2x -1 ×x -1
因式分解得(2x-1)(x-1)=0得x1=1,x2=1/2
X^2-3X+1=(2X-1)(X-1)=0;所以X1=1,X2=1/2