人气:443 ℃ 时间:2019-08-18 09:39:12
解答
分两种情况讨论:
(1)当a+b+c≠0时,
∵
=
=
,
∴
=
=
=2;
(2)当a+b+c=0时,
则b+c=-a,
∴
=
=-1.
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