Question

determine o 6 termo da p.a (-4,1...)​

Answer 1

$a_1=-4\\ a_2=1$

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

$a_2=a_1+r\ \therefore\ r=a_2-a_1=1-(-4)\ \therefore\ \boxed{r=5}$

$a_6=a_1+5r=-4+5(5)\ \therefore\ \boxed{a_8=21}$