Question

Evaluate the summation of 2n+5 from n=1 to 12 29 36 216 432

Answer 1

$\bf \sum\limits_{n=1}^{12}\ 2n+5\implies \sum\limits_{n=1}^{12}\ 2n+\sum\limits_{n=1}^{12}\ 5\implies 2\sum\limits_{n=1}^{12}\ n+\sum\limits_{n=1}^{12}\ 5 \\\\\\ 2\cdot \cfrac{12(12+1)}{2}+(12\cdot 5)\implies 156+60\implies 216$