Write a formuls for the general term(nth term) of the arithmetic sequence. Do not use a recursion formula. Then use the formula for A to the n to find the indicated term of the sequence

Question

find a11: 12, 10, 8,...

Answer 1

The first term is a1
Every subsequent term is a constant number d greater than the one before so it goes:
a1
a2 = a1 + d
a3 = a1 + 2d
a4 = a1 + 3d
a5 = a1 + 4d
.....
an = a1 + (n-1)d

for example
a14 = a1 + 13*d

Answer 2

makes no sense that's how i was doing it and I came up with 3.5

a11 = 12 + 10(.8444) = 3.5

however the answers to choose from are

.32
-8
-10
.34

Answer 3

Write a formula for the sequence below. Then find a11

{-2, 5, 12, 19, …}