Jawabanmu

2014-04-08T01:46:27+07:00
B= \frac{-128-16}{5-2} =  \frac{-144}{3} =48
a=-128-48=-176
un=a+(n-1)b
    =-176+(8-1)48
    =-176+7.48
    = -176+336
    =160
2014-04-08T06:15:16+07:00
U5/U2=ar4/ar=16/-128=r3=-0,125 r=-0,5 U5=16 a.-0,5^4=16 a=16/0,0625=256 U8=ar7=256.-0,5^7 =256.-0,0078125=-2