Question

Here are the first four terms of an arithmetic sequence.

5
12
19
26
Write down an expression, in terms of n, for the nth term of the sequence.

Answer 1

nth term = 7n - 2

Explanation:

The first 4 term of the arithmetic sequence is 5, 12 , 19 and 26. The expression in terms of nth term that model this sequence can be express below

The nth term of the arithmetic sequence form can be represented as follows.

nth = a + (n - 1)d

where

a = first term

d = common difference

Therefore,

a = 5

d = 12 - 5 = 7 or 19 - 12 = 7 or 26 - 19 = 7

nth = a + (n - 1)d

nth term = 5 + (n - 1)7

nth term = 5 + 7n - 7

nth term = 7n - 2