Question

Em uma PA o 7° termo vale -49 e o primeiro vale -73. Qual a razão dessa P.A?

Answer 1

$a_{1} =-73\\ a_{n} = a_{7} =-49\\ n=7\\ r=?\\\\\\ a_{n} = a_{1} +(n-1)*r\\\\\\ -49=-73+(7-1)*r\to\\\\ -49=-73+6*r\to\\\\ -49+73=6r \\\\ 24=6r\to \\\\ \frac{24}{6} =r\to \\\\ r=4$

Answer 2

Bom Dia!

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Dados:

a1 → -73

n→ 7

r → ?

an → -49

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An=a1+(n-1)·r

-49=-73+(7-1)·r

-49=-73+6r

-49+73=6r

6r=24

r=24/6

r=4

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Att;Guilherme Lima