Question

qual o vigesimo termo da progressao aritmetica (-8,-3,2,7,...)?

Answer 1

Espero ter ajudado, se quiser mais ajuda mande o link da pergunta no meu perfil.

7-2=5
2-(-3)=5
-3-(-8)=5
7+5=12

15x5=75
75+12=87

Answer 2

$\begin{array}{l}\sf a_n=a_1+(n-1)\cdot r\\\\\sf a_{20}=-8+(20-1)\cdot5\\\\\sf a_{20}=-8+19\cdot5\\\\\sf a_{20}=-8+95\\\\\boxed{\boxed{\sf a_{20}= 87}} \end{array}$