Jawabanmu

2014-03-20T18:41:22+07:00
S12 = 12:2 (2 x -3 + (12-1) -3)
= 6 (-6 - 33)
=6(-39)
=-234

maaf kalo salah
2014-03-20T18:59:09+07:00
A=-3
b= -6-(-3)= -3
s12 = n/2 (a+(n-1) b)
s12=12/2 (-3+(12-1)-3)
s12= 6 (-3+11.-3)
s12=6 (-3+(-33))
s12= 6 (-36)
s12= -216. munkin itu,,, tpi law fals sory ya,,,