Find an equation for the nth term of the arithmetic sequence.

a16 = 21, a17 = - 1

Answer:nth term=a1 - 27n + 27

Step-by-step explanation:

first term = a1

common difference=d=-1-21

d=-27

Using the formula

Tn=a1 + d x (n-1)

nth term=a1 + (-27) (n-1)

nth term=a1 - 27n + 27