Respostas

2014-02-19T19:49:47-03:00
A1=1
r= -11
an=186
n?
an= a1+(n-1).r
186=1+n.(-11)
186= 1-11n+11
186= 12-11n
11n= 12-186
11n= -177
n= -177/11
1 1 1