11.find the sum of the 1st 200 term of the goemetric sequence 9,-9,9,-9
a. 1,800
b. -1,800
c. 9
d. 0

12.find the sum of the 1st 8 term of 5, 10, 20,...?
a. 540
b. 640
c. 740
d. 940

13.what is the sum of the first 9 terms of 2, -6, 18, -54,...?
a. 10,122
b. -12,122
c. 13,122
d. -14,122

14.what is the sum of infinity of 1/2, 1/6, 1/18?
a. 3/4
b. 1/2
c. 1/10
d. 1/4

15.which of the following geometric series?
a. 4, 8, 16, 32
b. 8, 4, 2, 1
c. 1, 2, 4, 8
d. 1, 4, 16...​