Question

Encontre o 7° termo da PA 5,20,35
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Answer 1

$\left\{a_1,a_2,a_3,\dots\right\}=\left\{5,20,35,\dots\right\}$

$\boxed{a_n=a_k+(n-k)r}$

$a_2=a_1+r\ \therefore\ r=a_2-a_1=20-5\ \therefore\ \boxed{r=15}$

$a_7=a_1+6r=5+6(15)\ \therefore\ \boxed{a_7=95}$