Question

Find the 13th term of the arithmetic sequence -3x+7, -5x+3, -7x-1, ...

Answer 1

Answer:

a₁₃ = - 27x - 41

Step-by-step 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 = - 3x + 7

d = a₂ - a₁ = - 5x + 3 - (- 3x + 7)

                 = - 5x + 3 + 3x - 7

                 = - 2x - 4

Then

a₁₃ = - 3x + 7 + 12(- 2x - 4)

     = - 3x + 7 - 24x - 48

     = - 27x - 41