We have changed our privacy policy. In addition, we
use cookies on our website for various purposes. By continuing on our website, you consent
to our use of cookies. You can learn about our practices by reading our
privacy policy.

Find the 7^{th} term of the sequence using the explicit rule provided.

Plug the first term, seventh term, and common difference into the partial sum formula for arithmetic series.

Simplify to obtain your solution.

Example 2

Evaluate:

This is the same thing as being asked to find the 14^{th} partial sum of {a_{n}} = -4n + 20. All we need to do to evaluate this partial sum is to find the number of terms as well as the first and last terms.