Question

What is the 10th term of the sequence -4, -1, 2, 5

Answer 1

23

Explanation:

Note there is a constant difference between consecutive terms

- 1 - (- 4) = - 1 + 4 = 3

2 - (- 1) = 2 + 1 = 3

5 - 2 = 3

This indicates that the sequence is arithmetic with n th term

`a_(n)` = a₁ + (n - 1)d

where a₁ is the first term and d the common difference

Here a₁ = - 4 and d = 3, thus

`a_(10)` = - 4 + (9 × 3) = - 4 + 27 = 23