Hello from MrBillDoesMath!
Answer:
-18
Discussion:
I immediately noticed that 9/16 times -2 is the next term (-9/8) and -9/8 times -2 is, again, the next term (9/4). Continuing like this gives
(9/4) * (-2) = - 9/2
(-9/2)*(-2) = 9
9 * (-2) = -18
which is the desired answer
Thank you,
MrB