2楼saicjane
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发表于 2014-1-16 08:34
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设X-1=Y
=6Y^4+(Y+1)(2Y+1)(3Y-1)(4Y-1)
=6Y^4+(Y+1)((3Y-1)(2Y+1)(4Y-1)
=6Y^4+(3Y^2+2Y-1)(3Y^2+2Y-1+5Y^2)
=6Y^4+5(3Y^2+2Y-1)Y^2+(3Y^2+2Y-1)^2
十字相乘
=(2Y^2+3Y^2+2Y-1)(3Y^2+3Y^2+2Y-1)
=(5Y^2+2Y-1)(6Y^2+2Y-1)
带入X
=(5X^2-8X+2)(6X^2-10X+3).