Solve the problem.
-Find the sum of the first ten terms of the sequence $- 6 , - 1,4,9 , \ldots , 39$ where 39 is the tenth term.
A) 330
B) 170
C) 160
D) 165

Question

Quizplus · Accepted Answer

The given sequence is an arithmetic sequence where each term increases by 5. The first term $a = -6$ and the common difference $d = 5$. The sum of the first $n$ terms of an arithmetic sequence is given by $S_n = \frac{n}{2}[2a + (n-1)d]$. Substituting $n = 10$, $a = -6$, and $d = 5$, we get $S_{10} = \frac{10}{2}[2(-6) + (10-1)5] = 5[-12 + 45] = 5 \times 33 = 165$.

Solve the Problem −6,−1,4,9,…,39- 6 , - 1,4,9 , \ldots , 39−6,−1,4,9,…,39

Solve the Problem $- 6 , - 1,4,9 , \ldots , 39$