For this case we have that by definition, the GCF (Greatest Common Factor) is the largest integer that divides the numbers.
We have the following expressions:
[tex]9ab ^ 2\\6bc ^ 2[/tex]
We find the factors of 9 and 6:
[tex]9: 1,3,9\\6: 1,2,3,6[/tex]
Thus, the largest number that divides 9 and 6 is 3
It is also observed that "b" is the common variable of both expressions
Therefore, the GCF of the expressions is:
[tex]3b[/tex]
Answer:
[tex]3b[/tex]