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$$\sum_{0 \le k \le n^2} 7k+6x$$

(I need this answer urgent , please help me ,thanks in advance)

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Why is the answer needed urgently? –  anorton Dec 14 '12 at 14:58
    
Perhaps an exam is being taken... –  David Mitra Dec 14 '12 at 15:00
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yes , it is all about exam –  Shuvro Shuvro Dec 14 '12 at 15:07
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1 Answer 1

$\sum_{k=0}^{n^2} (7k+6x)=7\sum k+6x\sum 1=\frac{7n^2(n^2+1)}{2}+6x(n^2+1)=\frac{(7n^2+12x)(n^2+1)}{2}$

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thanks Jasper Loy –  Shuvro Shuvro Dec 14 '12 at 15:08
    
@Jasper Why did you erase the eloquent (I need this answer urgent , please help me ,thanks in advance)? –  Did Dec 14 '12 at 15:19
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