Work Step by Step
In an arithmetic sequence, the common difference can be calculated as the difference of any two subsequent terms: $d=a_2-a_1=3-7=-4$ The first term is: $a_1=7$.
You can help us out by revising, improving and updating this answer.Update this answer
After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.