Question

What is a formula for the nth term of the given sequence? -10, -19, -28

Answer 1

`a_(n)` = - 9n - 1

Explanation:

There is a common difference between consecutive terms , that is

- 19 - (- 10) = - 28 - (- 19) = - 9

This indicates the sequence is arithmetic with nth term

`a_(n)` = a₁ + (n - 1)d

where a₁ is the first term and d the common difference

Here a₁ = - 10 and d = - 9 , then

`a_(n)` = - 10 - 9(n - 1) = - 10 - 9n + 9 = - 9n - 1