Question

What is the common ratio of the geometric sequence below?

Answer 1

-1/3

Explanation:

18/-1/3= -6

and

-6/-1/3= 2

Answer 2

`\large\boxed{C.\ -(1)/(3)}`

Explanation:

`a_1,\ a_2,\ a_3,\ ...,\ a_n-\text{geometric sequence}\\\\r=(a_2)/(a_1)=(a_3)/(a_2)=(a_4)/(a_3)=...=(a_n)/(a_(n-1))-\text{common ratio}\\\\\\\text{We have}\\\\a_1=18,\ a_2=-6,\ a_3=2,\ a_4=-(2)/(3),\ ...\\\\(a_2)/(a_1)=(-6)/(18)=-(6:6)/(18:6)=-(1)/(3)\\\\(a_3)/(a_2)=(2)/(-6)=-(2:2)/(6:2)=-(1)/(3)\\\\(a_4)/(a_3)=(-(2)/(3))/(2)=-(2)/(3)\cdot(1)/(2)=-(1)/(3)`