Question

determine o 67 temo da PA (3,15,27...)

Answer 1

r = 15 - 3 => 12

an = a1 + (n - 1).r
a67 = 3 + (67 - 1).12
a67 = 3 + 66.12
a67 = 3 + 792
a67 = 795

Answer 2

r = 12
n = 67
a1 = 3
an = a1+(n-1).r => an= 3+(67-1).12 => an= 3+ 66x12 => an=795