依据(a1x+c1)(a2x+c2)=a1a2x^2+(a1c2+a2c1)x+c1c2得：3X^2+2X-1=3×1·x + （3×1+1×（-1））x + 1×（-1）=(3x+1)(x-1)因为算式结果为0所以，x=-1/3或1
(3x-1)(x+1)=0
(x+1)(3x-1)=0x=-1或x=1/3
3x2+2x-1=0(3x+1)(x-1)=0∴x1=-1/3 x2=1
