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

n_n = n_n-1 + 7

Explanation:

All it does is it adds 7 to the previous term

n = n_(previous)+7

Answer 2

nth term = 7n - 2

Explanation:

a = first term = 5

d = common difference = second term - first term

= 12 - 5 =7

d = 7

`a_(n) =` a + (n-1)d

= 5 + (n -1)7

= 5 + 7n - 7 {add like terms}

= 7n - 2