Question

Dada sequência (-1, 3, 7, ...) determine:

A) O primeiro termo
B) A razão
C) A70

me ajudem, Please

Answer 1

$A)\ -1\\\\B)3-(-1)=3+1=\ \textgreater \ r=4\\\\C)\\a_n=a_1+(n-1)r\\a_{70}=-1+(70-1)4\\a_{70}=-1+69\cdot4\\a_{70}=-1+276\\\\\boxed{\boxed{a _{70}=275}}$