Question

Determine o 17º termo da P.A.( -12, -8, -4, 0, 4, ...)

Answer 1

$\mathrm{Progress\tilde{a}o\ aritm\acute{e}tica}\Longrightarrow \{a_1,a_2,a_3,\dots\}\Longrightarrow\{-12,-8,-4,\dots\}$

$\boxed{a_n=a_k+(n-k)r}\Longleftarrow\mathrm{Termo\ geral\ de\ uma\ PA.}$

$a_2=a_1+r\Longrightarrow r=a_2-a_1=-8-(-12)\ \therefore\ \boxed{r=4}$

$a_{17}=a_1+16r=-12+16(4)\ \therefore\ \boxed{a_{17}=52}$