Respuesta :

The common ratio of this sequence is -3. This is evident because the 6/-2 is -3, and we know it is a sequence so the rule consistently applies.

Answer:  The required common ratio of the given geometric sequence is -3.

Step-by-step explanation:  We are given to find the common ratio of the following geometric sequence :

-2,   6,   -18,   54,   .    .    .

We know that

if a(n) denotes the nth term of a geometric sequence, then the common ratio is given by

[tex]r=\dfrac{a_{n+1}}{a_{n}}.[/tex]

For the given sequence, we see that

[tex]\dfrac{a(2)}{a(1)}=\dfrac{6}{-2}=-3,\\\\\\\dfrac{a(3)}{a(2)}=\dfrac{-18}{6}=-3,\\\\\\\dfrac{a(4)}{a(3)}=\dfrac{54}{-18}=-3,\\\\\vdots[/tex]

Therefore, the common ratio is given by

r = -3.

Thus, the required common ratio of the given geometric sequence is -3.