Question

write an explicit formula for the sequence 8, 6, 4, 2, 0, ... Then find a(down)14

Answer 1

you're subtracting by 2 each time

Answer 2

so the common difference is d = -2

Answer 3

the first term is 8, so a1 = 8

Answer 4

an = a1 + d(n-1)


an = 8 + (-2)(n-1)


an = 8 - 2n + 2


an = -2n + 10


So the explicit formula is an = -2n + 10


Does this make sense?