Question

Given the first five terms of the sequence 19, 15, 11, 7, 3 . . .
, use subscript notation to describe a7
.(1 point)

a7=−4


a7=−5


a7=−1


a7=−9

Answer 1

The sequence is arithmetic with common difference −4. Using subscript notation:
a_n = 19 + (n−1)(−4) = 19 − 4(n−1).
So a_7 = 19 − 4(6) = 19 − 24 = −5.