Find the indicated partial sum for the sequence with the given general term.
-$s _ { 3 } , a _ { n } = ( n + 4 ) ( n - 8 )$
A) $- 106$
B) 106
C) 182
D) $- 71$

Question

Quizplus · Accepted Answer

The partial sum $s_3$ means we sum the first three terms of the sequence. The general term is given by $a_n = (n + 4)(n - 8)$. We calculate the first three terms:- For $n = 1$: $a_1 = (1 + 4)(1 - 8) = 5 \times -7 = -35$- For $n = 2$: $a_2 = (2 + 4)(2 - 8) = 6 \times -6 = -36$- For $n = 3$: $a_3 = (3 + 4)(3 - 8) = 7 \times -5 = -35$Summing these gives $s_3 = -35 - 36 - 35 = -106$.

Find the Indicated Partial Sum for the Sequence with the Given