Respostas

2013-06-16T15:52:26-03:00

A_{n} = A_{1} + (n-1) \cdot r A_{20} = 30 A_{1} = -8 n = 20 r = ? 30 = -8 + (20 - 1) \cdot r 19r = 38 r = 2[text]A_{n} = A_{1} + (n-1) \cdot r [/text]

[text]A_{20} = 30 [text]A_{1} = -8[/tex][text]n = 20[/tex][text]r = ?[/tex][text]30 = -8 + (20 - 1) \cdot r[/tex][text]19r = 38[/tex][text]r = 2[/tex]