Jawabanmu

2014-03-19T23:15:16+07:00
U3 = ar^2 = 18
U6 = ar^5 = 486

ar^5 / ar^2 = 486 / 18
r^3 = 27
r = 3, a = 2

U5 = ar^4
     = 2 x 3^4
     = 2 x 81
     = 162
2014-03-20T08:22:34+07:00
U3 = ar^2 = 18
U6 = ar^5 = 486

ar^5 / ar^2 = 486 / 18
r^3 = 27
r = 3, a = 2

U5 = ar^4
     = 2 x 3^4
     = 2 x 81
     = 162