Hi! ❄
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
The rule for this sequence is 'multiply by -6'.
Verification ↓
-3*(-6)
18
18*(-6)
-108
So the rule for the sequence is 'multiply by -6'
And the Common ratio is -6.
Hope that made sense !!
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Step-by-step explanation:
Parallelogram
Reflect y=-1 ;x changes sign