Question

What is the 40th term of the arithmetic sequence? 21, 18, 15, 12, 9,...

Answer 1

-96

Explanation:

it follows a 21 - 3(n -1) sequence, so 21 - 3(39) = -96

3 is being subtracted (n-1) times, where n is the term number.

it starts with 21, so we have 21 - 3(n -1).