Question

observe a sequencia (-1,4,9...) determine a20?? pfv me ajudeem

Answer 1

PA(-1,4,9,...)

9-4 = 5
4-(-1) = 5

A1 = -1
R = 5


A20 = A1+19.r
A20 = -1+19.5
A20 = -1+95
A20 = 94         <<< Resposta