x²-2x-4=0由根与系数关系知：x1+x2=2,x1x2=-4x2/x1+x1/x2=(x2²+x1²)/x1x2=[(x1+x2)²-2x1x2]/x1x2=(2²+8)/(-4)=12/(-4)=-3明教为您解答,请点击[满意答案];如若您有不满意之处,请指出,我一定...