What is the expression for the nth term of the given sequence 15, 12, 9, 6, …

The given sequence is a decreasing arithmetic sequence, where each term is 3 less than the previous term.

The nth term of an arithmetic sequence can be found using the formula:

a_n = a_1 + (n - 1) * d

where: a_n is the nth term a_1 is the first term d is the common difference

In this sequence, a_1 = 15 (the first term) and d = -3 (each term is 3 less than the previous one).

Substituting these values into the formula gives:

a_n = 15 + (n - 1) * -3

Simplifying this gives:

a_n = 18 - 3n

So, the nth term of the sequence is 18 - 3n.