计算-4a(2a2+3a-1)的结果是( ) A.-8a3+12a2-4a B.-8a3-12a2+1 C.-8a3-12a2+4a D.8a3+12a2+4a
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化简x-(x-1)的结果是( ) A.x+ B.x- C.x-1 D.x+1
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单项式4x5y与2x2(-y)3z的积是( ) A.8x10y3z B.8x7(-y)4z C.-8x7y4z D.-8x10y3z
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已知-a2b·mab2=-3a3b3,则m等于( ) A. B.6 C.- D.-6
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下面的计算对不对?如果不对,应怎样改正? (1)3a2·4a3=7a5;(2)2x3·3x4=5x12;(3)3m2·(-5m2)=-15m2.
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计算:3x2y(-4xy2)·(x3)2=_________.
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计算:x2y3·xyz=_________;
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计算:2ab2·a3=________;
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计算:2x5·5x2=_________;
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求(-)1998·91999的值.
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