Question

Find the 15th term of the arithmetic sequence -5x+3−5x+3, -9x-2−9x−2, -13x-7,.......???

Answer 1

- 61x - 67

Explanation:

The n th term of an arithmetic sequence is

`a_(n)` = a₁ + (n - 1)d

where a₁ is the first term and d the common difference

d = - 9x - 2 - (- 5x + 3)

= - 9x - 2 + 5x - 3

= - 4x - 5 and a₁ = - 5x + 3, thus

`a_(15)` = - 5x + 3 + 14(- 4x - 5) = - 5x + 3 - 56x - 70 = - 61x - 67