Question

The nth term of a sequence is 25 - 3n

Work out the first three terms of the sequence
Work out the first negative term of the sequence

Answer 1

see explanation

Explanation:

To find the first 3 terms substitute n = 1, 2, 3 into the formula

(a)= 25 - (3 × 1) = 25 - 3 = 22 = 25 - (3 × 2) = 25 - 6 = 19= 25 - (3 × 3) = 25 - 9 = 16

The first three terms are 22, 19, 16

Note the difference between consecutive terms is - 3

19 - 22 = 16 - 19 = - 3

Continuing this pattern

(b)16 - 3 = 13 13 - 3 = 10 10 - 3 = 7 7 - 3 = 4 4 - 3 = 1 1 - 3 = - 2

The first negative term is - 2