Question

What is the common ratio of the sequence -2, 6, -18, 54

Answer 1

The common ratio of a geometric sequence is the ratio of any term to the one before it. Here, you can find it by

... 6/-2 = -3

or, if you prefer the minus sign in the numerator, ...

... -18/6 = -3

or the ratio of any other sequential terms.

The common ratio is -3.