Question

if the nth term of an ap 21, 18, 15,....is 0. find n​

Answer 1

Answer:

n = 8.

Step-by-step explanation:

$a = 21 \\ \\ d = - 3 \\ \\ a + (n - 1)d = 0 \\ \\ 21 + (n - 1)d = 0 \\ \\ 21 - 3(n - 1) = 0 \\ \\ 21 = 3(n - 1) \\ \\ n - 1 = 7 \\ \\ n = 8.$

Answer 2

Step-by-step explanation:

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