Question

determine o 13*termo da P.A.(1,7,15,...)

Answer 1

r = a₂ - a₁
r = 7 -1
r = 6

$A_{n} = a_{1} + (n -1) . r$a13 =1 + (13 - 1) . 6
a13 = 1 + 12 . 6
a13 = 73