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已知方程x2-3x+1=0的两根是x1,x2;则:x12+x22=______,
1
x1
+
1
x2
=______.
人气:134 ℃ 时间:2019-11-16 13:35:48
解答
由题意知,x1+x2=
b
a
=3,x1x2=
c
a
=1,
x12+x22=(x1+x22-2x1x2=9-2=7,
1
x1
+
1
x2
=
x1+x2
x1x2
=3,
故填7;3.
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