Question

YEAR 9 MATHS- SEQUENCES

Here are the first five terms of a linear sequence.
9 15 21 27 33 ...
Work out the nth term

Answer 1

see below

Explanation:

This is an arithmetic sequence. The explicit formula for an arithmetic sequence is aₙ = a₁ + (n - 1)d where a₁ is the first term and d is the common difference. In this case a₁ = 9 and d = 6 so we have:

aₙ = 9 + (n - 1) * 6

aₙ = 9 + 6n - 6

aₙ 6n + 3