Respuesta :

Answer:

12

Step-by-step explanation:

Let the unknown number be x.

8 = -4(1) + x

8 = -4 + x

x - 4 = 8

x = 8 + 4

x = 12

Answer:

[tex]a_{n}[/tex] = - 4n + 12

Step-by-step explanation:

The n th term of an arithmetic sequence is

[tex]a_{n}[/tex] = a₁ + (n - 1)d

where a₁ is the first term and d the common difference

Here a₁ = 8 and d = a₂ - a₁ = 4 - 8 = - 4 , then

[tex]a_{n}[/tex] = 8 - 4(n - 1) = 8 - 4n + 4 = - 4n + 12