Question

determine o termo a58 da pa (12,15,18,21...0

Answer 1

$r=a_2-a_1\\r=15-12\\r=3\\\\a_n=a_1+(n-1)r\\a_{58}=a_1+(58-1)3\\a_{58}=12+57\cdot3\\a_{58}=12+171\\a_{58}=183$



Espero ter ajudado.
Bons estudos! :)