# How can I evaluate the following $\sum_{0 \le k \le n^2} 7k+6x$

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

-
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
yes , it is all about exam –  Shuvro Shuvro Dec 14 '12 at 15:07
$\sum_{k=0}^{n^2} (7k+6x)=7\sum k+6x\sum 1=\frac{7n^2(n^2+1)}{2}+6x(n^2+1)=\frac{(7n^2+12x)(n^2+1)}{2}$