Answer:
-3
Step-by-step explanation:
GCF = greatest common factor
What is in common with 3x and 18? They are both multiples of 3.
3 times x = 3x
3 times 6 = 18
However, it is -3x and -18
So we can add a negative sign in front of the 3
Therefore, the GCF is -3.
I hope this helped and please mark me as brainliest!
