Jawabanmu

2014-02-02T15:00:13+07:00
2014-02-02T15:31:49+07:00
U9 =768     U5= 48
U9/U5 = ar^8/ar^4 
768/48 = r^4
   16 = r^4
     r  = 2

U7= ar^6 = ar^8/r^2
               = 768/4
               =192