若方程x2-3x-1=0的两根为x1、x2,则x1+x2=_,1/x1+1/x2=_.
问题描述:
若方程x2-3x-1=0的两根为x1、x2,则x1+x2=______,
+1 x1
=______. 1 x2
答
x1+x2=-
=-b a
=3,-3 1
∵x1+x2=3,x1x2=
=c a
,-1 1
∴
+1 x1
=1 x2
=
x1+x2
x1x2
=-3.3 -1
故答案为:3,-3.