Question

12, 20, 28, 36,，
what does an equal

Answer 1

`a_(n)` = 8n + 4

Explanation:

There is a common difference d between consecutive terms, that is

d = 20 - 12 = 28 - 20 = 36 - 28 = 8

This indicates 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 = 12 and d = 8, thus

`a_(n)` = 12 + 8(n - 1) = 12 + 8n - 8 = 8n + 4