The simple formula for the nth term of an arithmetic sequence is an = 5n + 15. what is the explicit formula corresponding to the simple formula? a. an = 15 + 5n b. an = 15 + (n - 1)(5) c. an = 20 + (n)/(5) d. an = 20 + (n - 1)(5) e. an = 5 + (n - 1)(15)

Sequence will look like this:
Term 1: 20 20 + 5(0)
Term 2: 25 20 + 5(1)
Term 3: 30 20 + 5(2)
Term 4: 35 25 + 5(3)
ETC.

It cab noted that the numbers in the bracket (that is, 0, 1, 2, 3, 3, etc) = n-1

Then, the explicit formula will be;
an = 20 + 5(n-1).

The correct answer is D.