Răspunsuri

2014-11-09T19:30:22+02:00
D = 1 + 7 + 7² +........+7^2009    7D=7 + 7² + 7³ +.........+7^2010    7D - D = 6D =
= 7^2010 -1 ⇒ D = (7^2010 - 1 ) / 6
1 5 1