Answer:
3x
Explanation:
First, find the prime factorization of each of the terms:
[tex]\begin{gathered} -3x=-1\times3\times x \\ 6x=2\times3\times x \\ 12x=2\times2\times3\times x \end{gathered}[/tex]Next, pick the term that is common in the three products:
[tex]\begin{gathered} \text{GCF}=3\times x \\ =3x \end{gathered}[/tex]The GCF of -3x, 6x, and 12x is 3x.
