Question

How to find the sum of the first 73 terms of the arithmetic sequence 8, 9, 10, 11...?

Answer 1

`3212`

Explanation:

Find `a_73`
`a_73= 8+1(73-1)= 80`

Using this solve for the sum:
`S_n=n/2(a_1+a_n)`

`S_73= 73/2(8+80)=3212`