diketahui (x-3),(x-1),(2x-2),dan(2x+6) barisan geometri nilai + cara A.3. C.7 B.5. D.9

barisan geometri rasio r = U2/U1 = U3/U2
(x-1) / (x-3) = (2x-2) / (x-1)
(x-1) (x-1) = (2x-2) (x-3)
x^2 - 2x +1 = 2x^2 -8x+6
x^2 -2x^2 -2x + 8x +1 -6 = 0
-x^2 +6x -5 = 0
x^2 -6x +5 = 0
(x-5) (x -1) = 0
Jadi x = 5 atau x = 1, x = 1 tidak bisa karena suku awal x-1 = 1 -1 =0. Jadi x = 5