第一提 不用了
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第一提 不用了
![第一提 不用了](/uploads/image/z/1863874-10-4.jpg?t=%E7%AC%AC%E4%B8%80%E6%8F%90+%E4%B8%8D%E7%94%A8%E4%BA%86)
1、=[2(x²+6x+1)+(x²+1)][(x²+6x+1)+2(x²+1)]
=(3x²+12x+3)(3x²+6x+3)
=9(x²+4x+1)(x²+2x+1)
=9(x²+4x+1)(x+1)²
2、=(x+1)(x+7)(x+3)(x+5)+15
=(x²+8x+7)(x²+8x+15)+15
=(x²+8x)²+22(x²+8x)+105+15
=(x²+8x+12)(x²+8x+10)
=(x+6)(x+2)(x²+8x+10)
3、=(w^1980+w^1981+w^1982)+(w^1983+w^1984+w^1985)+……+(w^2007+w^2008+w^2009)
=w^1980(1+w+w²)+w^1983(1+w+w²)+……+w^2007(1+w+w²)
=0
每三个一组,分成十组,每一组提取一个公因式,括号里的和是0
=(3x²+12x+3)(3x²+6x+3)
=9(x²+4x+1)(x²+2x+1)
=9(x²+4x+1)(x+1)²
2、=(x+1)(x+7)(x+3)(x+5)+15
=(x²+8x+7)(x²+8x+15)+15
=(x²+8x)²+22(x²+8x)+105+15
=(x²+8x+12)(x²+8x+10)
=(x+6)(x+2)(x²+8x+10)
3、=(w^1980+w^1981+w^1982)+(w^1983+w^1984+w^1985)+……+(w^2007+w^2008+w^2009)
=w^1980(1+w+w²)+w^1983(1+w+w²)+……+w^2007(1+w+w²)
=0
每三个一组,分成十组,每一组提取一个公因式,括号里的和是0