Question

A recursive rule for the arithmetic sequence is a1=-3;an=an-1+7

Please help I'll add 50 points
Which represents the explicit rule for the same arithmetic sequence?

A. an=7n-10

B. an=7n+10

C. an=-3n-3

D.an=-3n-7

Answer 1

The explicit rule for any arithmetic sequence is:

a(n)=a+d(n-1), a=initial term, d=common difference, n=term number

In this case a=-3 and d=7 so:

a(n)=-3+7(n-1)

a(n)=-3+7n-7

a(n)=7n-10