Respuesta :

mhanifa

Answer:

aₙ = 30 - 5n

Step-by-step explanation:

25,20,15,10, ...

We see from the given series that it is AP with:

  • First term = 25
  • Common difference = -5 and it is decreasing series

Then formula is:

  • aₙ= a₁ + (n-1)d
  • aₙ= 25 + (n-1)(-5)
  • aₙ= 25 - 5n + 5
  • aₙ = 30 - 5n