x1,x2是方程x^2+4x-6=0两个根
x1+x2=-4,x1x2=-6
1)
x1x2^2+x1^2x2=x1x2(x1+x2)=-6*(-4)=24
2)
(x2/x1)+x1/x2
=(x1^2+x2^2)/x1x2
=[(x1+x2)^2-2x1x2]/x1x2
=(16-2*(-6))/(-6)
=-28/6
=-14/3
3)
(x1-x2)^2
=(x1+x2)^2-4x1x2
=16-4*(-6)
=40
4)
(x2-2)(x1-2)
=x1x2-2(x1+x2)+4
=-6-2*(-4)+4
=6