Theory
A sequence is a list of numbers in order. The term number tells you the position: first term, second term, third term, and so on.
A linear sequence changes by the same amount each time. This repeated change is called the common difference.
In a linear nth term, the common difference is the number in front of n.
To find the constant, work backwards one step from the first term to the term before the first term.
The nth term tells you how to find any term from its position. For example, if n = 10, you are finding the 10th term.
Always check your nth term by substituting n = 1 and n = 2 to see if it gives the first two terms.
Key rulenth term = common difference * n + term before the first term