Question

Find the 20th term of the arithmetic sequence 15,9,3,-3

Answer 1

Answer:

-99

Step-by-step explanation:

$a = 15 \\ d = - 6 \\ {n}^{th} term = a + (n + 1)d = 15 + (n - 1)( - 6) \\ {20}^{th} term =15 + (20 - 1)( - 6) = 15 - 114 = - 99$