(algebra 1) arithmetic sequences
question in the replies

Question

(algebra 1) arithmetic sequences 
question in the replies

gelphielvr · Answer

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Luigi0210 · Answer

Do you know the arithmetic sequence formula?

gelphielvr · Answer

a + (n – 1)^t

Luigi0210 · Answer

Well, close, it's actually:

$\large a_n = a_1 +(n-1)*d $

Where $a_1$ is the first term and d is the difference between the terms.

They already have you $a_1 $ which is $a_1 = -7$ 
To find d, just the find the difference between each term: -13 - (-10) = -3 
-10 -(-7) = -3 
-16 -(-13) = -3 and so on..

so we get d = -3

Just plug those into the formula:

$\large a_n = (-7) +(n-1)(-3) $

$\large a_n = -7 +(-3n+3 ) $

Giving you:

$\large a_n =  -3n -4 $ as your formula.

gelphielvr · Answer

thank you for the explanation luigi - its been weeks since I've done this so this really helped :]

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