Jawabanmu

2014-04-11T18:46:25+07:00
U2=a+b=6.....U7=a+6b=192....a+b+5b=192....6+5b=192.....5b=186...b=37, 2.....a=-31.2...S8=4 (-31, 2+37, 2×7)=916.8
oh ya geometry
tadi blm ada pilihannya jg di edit ya soalnya?
apa sy sakah baca :p
mungkin situ yang salah baca.. hehehe...
haha :p
2014-04-11T19:03:22+07:00
U2=ar=6   U7=ar^6=192
ar^6:ar=192:6 =>r^5=32 =>⁵√32 =2
U2=ar=6 => a(2)=6 => a=2
S₈= \frac{a(r x^{n}-1)}{r-1} => \frac{3(2^8 -1)}{2-1}
   =3(256-1) => 3(255)=765