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【单选题】
化简-3a?（2a 2 -a+1）正确的是（ ）A.
-6a 3 +3a 2 -3a
B.
-6a 3 +3a 2 +3a
C.
-6a 3 -3a 2 -3a
D.
6a 3 -3a 2 -3a
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