Question

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

Answer 1

an = a1 + ( n - 1 ).r

37 = 5 + ( n - 1 ).4

37 = 5 + 4n - 4

37 = 1 + 4n

37 - 1 = 4n

4n = 36

n = 36 / 4

n = 9



resposta ; 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