已知x1、x2是方程x2-3x-2=0的两根,不解方程,求值.(1)x1+x2(2)x1x2(3)x2x1+x1x

2025-02-26 09:28:52
推荐回答(1个)
回答1:

(1)x1+x2=3;
(2)x1x2=-2;
(3)原式=
x2+x2
x1x2
=
(x1+x2)2?2x1x2
x1x2
=
32?2×(?2)
?2
=?
13
2