Question

Find the 88th term of the arithmetic sequence 4, -1, -6, ...4,−1,−6,...

Answer 1

a₈₈ = - 431

Explanation:

The nth term of an arithmetic sequence is

`a_(n)` = a₁ + (n - 1)d

where a₁ is the first term and d the common difference

here a₁ = 4 and d = a₂ - a₁ = - 1 - 4 = - 5 , then

a₈₈ = 4 + (87 × - 5) = 4 + (- 435) = 4 - 435 = - 431

Answer 2

88th term = -431

to solve, keep subtracting 5