Question

Quantos termos tem a pa ( 5,10...7,8,5)

Answer 1

Resposta:

An = a1 + (n – 1) x r

An = 785;  a1 = 5 ; r = 10 – 5 = 5  e n = ?

An = 5 + (n-1)x5

785 = 5 + 5n -5

n = 785/5 -  n = 157 termos