Is the sequence -1,6,-36,216 geometric and what is the common ratio

  yes, -6

Step-by-step explanation:

6/-1 = -36/6 = 216/-36 = -6

Adjacent terms have a common ratio of -6, so they comprise a geometric sequence.

Dependent variable: y

Independent variable: 2x

Step-by-step explanation:

The dependent variable is the variable that relies on the independent variable for its value. In this situation, you can't have y without x.