Question

Find the nth term: 18, 30 ,42, 54

Answer 1

`a_n=6+12n`

Explanation:

This is an arithmetic sequence, the kind where you start with a number (first term), then add a specific number (the common difference) to get the next term, and on and on like that.

1st term: 18

2nd term: 18 + 12 = 30

3rd term: 30 +12 = 42

4th term: 42 + 12 = 54, etc.

`\vdots\\a_n=a_1+(n-1)d`

In this formula, n is the number of a term, and d is the common difference.

In this question,
`a_1=18 \text{ and } d=12`, so

`a_n=18+(n-1)12\\a_n=18+12n-12\\a_n=6+12n`

Answer 2

a^6-78

Explanation: