What the nth term of 9,11,13,15,17

Question

asked Feb 6, 2020 147k views

2 Answers

Francesco Donzello · Answer 1 · 2020-02-08T22:10:42+0000

Answer:

a_(n) = 2n + 7

Explanation:

Note the differences between consecutive terms are constant, that is11 - 9 = 13 - 11 = 15 - 13 = 17 - 15 = 2 ← common difference

Thus the sequence is arithmetic with n th term

a_(n) = a₁ + (n - 1)d

where a₁ is the first term and d the common difference

Here a₁ = 9 and d = 2, thus

a_(n) = 9 + 2(n - 1) = 9 + 2n - 2 = 2n + 7