## Precalculus (6th Edition) Blitzer

$-29300$
we have $a_1=4$ and $d=-6$ For an arithmetic sequence, we have $S_n=\dfrac{n}{2}(2a_1+(n-1)d)$ Now, $S_{100}=\dfrac{100}{2}(2(4)+(100-1)(-6))$ or,$=50(8+(-594))$ Thus, $S_{100}=-29300$