Find a formula for a_nfor the arithmetic sequence. 16,11,6,1,-4,... A)a_n= 1 - 5n B)a_n= 1 + 5n C)a_n= -5n + 21 D)a_n= 5n - 21 E)a_n= 5n + 21

Question

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The given sequence is an arithmetic sequence with a common difference of -5 (each term is 5 less than the previous term). The first term (n=1) is 16. To find the nth term, we use the formula for the nth term of an arithmetic sequence: $a_n = a_1 + (n-1)d$, where $a_n$ is the nth term, $a_1$ is the first term, and $d$ is the common difference. Substituting $a_1 = 16$ and $d = -5$, we get $a_n = 16 + (n-1)(-5) = 16 - 5n + 5 = 21 - 5n$, which matches choice C.

Find a Formula for An ​for the Arithmetic Sequence

Find a Formula for A_nfor the Arithmetic Sequence