16(x+3y)^4-0.25(x+3y)
=¼(x+3y)[64(x+3y)³-1]
=¼(x+3y)[4(x+3y)-1][16(x+3y)²+4(x+3y)+1]
=¼(x+3y)(4x+12y-1)[16(x+3y)²+4(x+3y)+1]第一步是怎么到第二部的？请告诉我一下具体步骤和公式好吗谢谢！16(x+3y)^4-0.25(x+3y)=¼(x+3y)×64(x+3y)³-¼(x+3y)×1=¼(x+3y)[64(x+3y)³-1] 提取公因式¼（x+3y)==¼(x+3y)(4x+12y-1)[16(x+3y)²+4(x+3y)+1] 立方差公式[a³-b³=(a-b)(a²+ab+b²)]