2x²-5x+2=0提取公因数2,得到:2(x²-5/2 x+1)=0将-5/2分解成(-1/2)+(-2)的和,且(-1/2)(-2)=1原式:2(x-1/2)(x-2)=0解为:x1=1/2,x2=2八年级数学,看得明白吗?
2x^2-5x+2=0x^2-5/2x+1=0x^2-5/2x+(5/4)^2 -(5/4)^2 +1=0(x-5/4)^2 =9/16x-5/4 =3/4或x-5/2 =-3/4x=2或x =1/2
x=2/3