Question

What are the explicit equation and domain for an arithmetic sequence with a first term of 5 and a second term of 2?

Answer 1

General equation is 

an = a1 + (n-1)d     where a1 = first term and d = common difference

here d= 2-5 = -3  and  a1 = 5

so an = 5 -3(n-1) is the explicit equation required.