Question

Quantos termos tem a P.A. (5,9,13,..,37)

Answer 1

a1=5
an=a1+(n-1)q
37=5+(n-1).4
n-1=8
n=9
9 termos

Answer 2

an= 37

a1= 5

n= ?

r= 9 - 5 = 4

an= a1 + (n - 1)r

37= 5 + (n - 1)4

37= 5 + 4n - 4

37= 1 + 4n

37 - 1 = 4n

36= 4n

n= 36/4

n= 9

Resposta: 9 termos