Jawabanmu

2014-07-20T21:21:30+07:00
U1 = a = -6
u9 = a+8b = 18
       -6 + 8b = 18
        b=3
bedanya 3, sehingga urutannya -6, -3, 0, 3, 6, 9, 12, 15, 18
jd a+d+g = -3 + 6 + 15 = 18
2014-07-20T21:24:15+07:00
U1 = a = -6
U9 = 18
     = a + 8b
 18 = -6 +8b
b=beda = 3
U2 =a =-3
U3= b= 0
U4 =c= 3
U5 = d= 6
U6=e= 9
U7=f= 12
U8= g= 15
a+d+g =-3 +6+15 =18
jawaban : D