How would I find the nth term of this sequence? 15, 18, 21, 24, ...

The nth term refers to the function which will have to be applied to the number of a term in a sequence in order to produce that term.The 1st term in this sequence is 15 the 2nd is 18 and the 3rd is 21. We must find what function can be applied to the numbers 1, 2 and 3 in order to produce 15, 18 and 21 respectively.To do this we must first find out by how much each term in the sequence is smaller or larger than the one which proceeds it.the difference between 18 and 15 is 3 and the same is true of 21 and 18.18 - 15 = 321 - 18 = 3This means that as the number of the term increases by one (from 1 to 2) the term must increase by 3. This would mean that the nth term must be 3 times the term number and of the form: nth term = 3n + XWhere X is a stand in for a number we do not yet know.If we write out the sequence 3n then we can see that the difference between that sequence and the one we are attempting to solve for is 12 and as such the sequence must be 3n + 12.Finally, we should check that our answer is correct by writing out the first terms of 3n + 12 and seeing that they are the same as the original sequence.