# Math Formula Part 2/3

I've done the second part to the Math Formula post. It was determine the 19th term of the sequence which I did.
Now it says..which of the numbers -268 and -350 are terms of the sequence?

I was doing something like this:
tn = -7 (-268) +19
I was plugging -268 as n. But that just confused me. How do I figure this out?

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1. No, you are trying to find n.

Phrased another way:
Which term in the sequence is equal to -268
let that term number be n
remember tn = a + (n-1)d
a =
d =
-268 = 12 + (n-1)(-7)
-280 = -7n + 7
-287 = -7n
n = 41

so the t41 = -268

Do the same thing for tn = 350
remember , that n has to be a positive whole number, or else there is not such term.

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