Resposta :
Nesta P.A., precisamos encontrar "r" e an:(a12).
[tex]r=a_{2}-a_{1}\\r=(-3)-(-8)=>-3+8=>r=5\\\\aplicamos\ agora\ o\ termo\ geral\\a_{n}=a_{1}+(n-1).r\\a_{12}=-8+(12-1).5\\a_{12}=-8+55\\\\a_{12}=47[/tex]
an = a1+r(n-1)
a12 = -8+5(12-1)
a12 = -8+5(11)
a12 = 47
PA(-8,-3,2,7,12,17,22,27,32,37,42,47)
a12 = 47
Espero ter ajudado (: