Math Formula Part 2/3
posted by Anonymous .
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?

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 + (n1)d
from your previous post
a =
d =
268 = 12 + (n1)(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.