Question

Terms and expressions of nth term

Answer 1

see explanation

Explanation:

(a)

there is a common difference between consecutive terms, that is

10 - 12 = 8 - 10 = 6 - 8 = 4 - 6 = - 2

this indicates the sequence is arithmetic with nth term

`a_(n)` = a₁ + (n - 1)d

where a₁ is the first term and d the common difference

here a₁ = 12 and d = - 2 , then

`a_(n)` = 12 - 2(n - 1) = 12 - 2n + 2 = 14 - 2n

(b)

similarly this is an arithmetic sequence

with a₁ = 25 and d = 20 - 25 = 15 - 20 = 10 - 15 = 5 - 10 = - 5

`a_(n)` = 25 - 5(n - 1) = 25 - 5n + 5 = 30 - 5n