Question

Find the indicated term in each arithmetic sequence.
$80$th term of$-1,1,3,...$

Short answer

The solution is$157$.

Step-by-step solution

Step 1. Given information 

Arithmetic sequence:$-1,1,3,...$

Step 2. Calculation 

The first term of the arithmetic sequence is $a_1=-1$, and the common difference is$d=2$.

Now, the $80$th term is -

$a_n=a_1+\left(n-1\right)d$

role="math" localid="1648710462061" $a_{80}=-1+\left(80-1\right)2$

$=-1+158$

$=157$