Respostas

2014-06-05T19:24:18-03:00
An = a1 + (n-1) . r
38 = -16 + 9 . r
38 + 16 = 9 . r
54 = 9 . r
r = 6
-16; -10; -4; 2; 8; 14; 20; 26; 32; 38.
R = 14