题目内容
化简: (0.3x3-x2y+xy2-y3)-(-0.5x3-x2y+0.3xy2)+(1.2x3-1.2y3)为
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A.2x3+0.7xy2-2.2y3 B.x3-0.7xy2
C. x3-1.7xy2-2.2y3 D.2x3-2.2y3