Question

write the explicit rule for the arithmetic sequence 9,13,17,21...A. an=9n-5B.an=-9n+14C.an=-4n+5D.an=4n+5

Answer 1

Given the arithmetic sequence:

9 , 13 , 17 , 21 , ......

The common difference = 13 - 9 = 17 - 13 = 21 - 17 = 4

The first term is 9

so, the explicit rule is an = 9 + 4 ( n - 1)

an = 9 + 4n - 4

an = 4n + 5

The answer is option D.