Jawabanmu

2014-03-06T11:52:19+07:00
Sn = 4n²-3n

s9-s8 = u9
(4.9²-3.9)-(4.8²-3.8) = u9
(324-27)-(256-24) = u9
297-232 = u9
65 = u9

Semoga membantu :D