Question

Quantos termos tem a P.A(5,10...,785)?

Answer 1

An = A₁ + (n - 1) . r
785 = 5 + (n - 1) . 5
785 = 5 + 5n - 5
785 = 5n

n = 157

Answer 2

Bom Dia!

Dados:

a1 → 5

an → 785

r → a2-a1 → 10-5 = 5

n → ?

________________

An=a1+(n-1)·r

785=5+(n-1)·5

785=5+5n-5

785-5n=5-5

-5n=0-785

-5n=-785 (-1)

5n=785

n=785/5

n=157

_______________

Att;Guilherme Lima