Find the term n=20, given the arithmetic sequence a_1=−4 and d=-9

eukrasicx

eukrasicx

Answered question

2022-10-06

Find the term n=20, given the arithmetic sequence a 1 = - 4 and d=-9

Answer & Explanation

Shania Delacruz

Shania Delacruz

Beginner2022-10-07Added 7 answers

An arithmetic sequence has the general term given by
a n = a 1 + ( n - 1 ) d
Then applying given values
a n = - 4 + ( n - 1 ) ( - 9 ) = - 4 - 9 n + 9 = - 9 n + 5
For n=20, we have a 20 = - 9 · 20 + 5 = - 175

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