如圖,四面體ABCD中,G為△ABC的重心,
=2,以
{,,}為基底,則
=______.

∵
=+,
=,
=(+),
=+,
=,
=-,
=,
=-.
∴
=×(+)+
(-)+
(-)=-
+
.
故答案為:
-+.
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