Jawabanmu

2014-02-02T14:10:28+07:00
U5/U2 = ar^4/ ar = 16/-2
maka r^3 = -8
maka r = -2
jika ar = -2, maka a =1
maka U7 = ar^6 = 1.(-2)^6 = 1*64 = 64
2014-02-02T14:11:19+07:00
U2= a.r
a.r=-2
u5=a.r^4
a.r^4=16
a.r=-2
a.r^4=16
a=-2/r
-2/r.r^4=16
-2.r^3=16
r^3=-8
r=-2
a.r=-2
a=1
u7=a.r^6
1.-2^6=64