Question

What is the sum of the first 10 terms in this geometric sequence? 3,-6,12,-24

Answer 1

3(-2)= -6
-6(-2)= 12
12(-2)= -24
-24(-2)= 48
48(-2)= -96
-96(-2)= 192
192(-2)= -384
-384(-2)= 768
768(-2)= -1536

-1536 is the tenth term in this geo-sequence

Answer 2

3,-6,12,-24,48,-96,192,-384,768,-1536

sum:
3 -6+12 -24+ 48 -96+ 192 -384+ 768 -1536 = -1023

Answer is C. -1023