Answer:
![a_1=7](https://img.qammunity.org/2021/formulas/mathematics/middle-school/1wtqqqdtkaq2pmdqmsxbanla91uf8eigj7.png)
![a_2=7\\a_3=10\\a_4=13\\a_5=16](https://img.qammunity.org/2021/formulas/mathematics/middle-school/pev264wqmk8zyw0nls8ljo7wl4zgmvj6uk.png)
Explanation:
The arithmetic series is
![S_(5)=\sum_(k=1)^5(1+3k)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/gn10lz1piml8u7jur7f77kz3w1zdu1hdm6.png)
From the given series the general term of the series is
![a_k=1+3k](https://img.qammunity.org/2021/formulas/mathematics/middle-school/avsm09y054qs7admkdlmake596qtosnvs4.png)
When
, we substitute into the general formula to get:
![a_1=1+3(1)=4](https://img.qammunity.org/2021/formulas/mathematics/middle-school/80zboeghusg0l6eh1n574k7qjj6llq4w3z.png)
When k=2, we get:
![a_2=1+3(2)=7](https://img.qammunity.org/2021/formulas/mathematics/middle-school/i7l2w7hnjersypbae04z8t41wp5aiayl3v.png)
When k=3, we substitute to get:
![a_3=1+3(3)=10](https://img.qammunity.org/2021/formulas/mathematics/middle-school/6iq31fy7pa769le6s6pyya39iriwlh96fn.png)
When k=4, we substitute to get:
![a_4=1+3(4)=13](https://img.qammunity.org/2021/formulas/mathematics/middle-school/8cn5wbe6unefsxxmw2winz56k21f7wda23.png)
When k=5, we get:
![a_5=1+3(5)=16](https://img.qammunity.org/2021/formulas/mathematics/middle-school/djn88enjnytu83dvmmqgx33ifjs0zd8dx9.png)