Question

Find the sum of the following $AP$.
$-37,-33,-29,.....,$ to $12$ terms

Answer 1

Given that ,

$a=-37,d=-33-(-37)=4,n=12$

Sum of A.P.

$=\frac{n}{2}(2a+(n-1\left)d\right)$

$sum=\frac{12}{2}[2\times (-37)+(12-1)\times 4]$

$=-180$