tolong dibantu jawab yh...

A) 2, 6, 18,. r = 6/2 = 18/6 = 3
B) 12, 4, 1, r = 4/12 = (1 1/3)/4 = 1/3 (1 1/3 : 4 = 4/3:4 = 1/3)
c) 3, 12, 48 ==» r = 12/3 = 48/12 = 4
d) 4, -8, -16 (bukan barisan geometri)
E) 2, -2, 2 ==» r = -2/2 = 2/-2 = -1
f) 1/9, 1/3, 1 ==» r = (1/3)/(1/9) = 1/(1/3) = 3