Answer:
The third choice is the one you want.
Step-by-step explanation:
The formula for an arithmetic sequence is as follows:
[tex]a_{n}=a_{1}+d(n-1)[/tex]
Our first number is 8, so a1 = 8. If the second term is 5, then d = -3. Filling in our formula gives us this:
[tex]a_{n}=8-3(n-1)[/tex]
Now we need domain. Our choices are n ≥ 1 and n ≥ 0 so let's try both. Replace n in the formula with each one, one at a time, and see what the result is.
If n ≥ 0:
[tex]a_{0}=8-3(0-1)[/tex] so [tex]a_{0}=8-(-3)[/tex] which gives you that the first term, defined by [tex]a_{0}[/tex] is 11. That's not correct. Let's check n ≥ 1[tex]a_{1}=8-3(1-1)[/tex]
and [tex]a_{1}=8-0[/tex] which is 8, the first term.
