（4x+______）2=16x2+______+9y2．
根据题意得：（4x+3y）2=16x2+24xy+9y2．
故答案为：3y；24xy
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A. I'm sorry. I'm new here.
B. Why do you ask me?
C. Who knows.
说明硬蜱与软蜱的主要形态与生活习性差异
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