If the common difference in an arithmetic sequence is 4, and the 20th term is 36, what is the first term?A.-40 B. 76 C. 40 D. 2

asked Mar 9, 2021 106k views

3 votes

by Eres

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5 votes

Answer:

Explanation:

$a_n=a_1+d(n-1)\\\\a_(20)=a_1+d(20-1)\\\\36=a_1+4\cdot19\\\\36=a_1+76\\\\a_1=36-76\\\\a_1=-40$

Noixes answered Mar 14, 2021

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