Answer :

3(4x-3)
First, find the GCF of both numbers.
The gcf of 12 and 9 is 3.
Then you divide it by both numbers.
Divide 12x by 3 is 4x and 9 by 3 is 3.
0000000
Their GCF is 3, so:
12x-9=3(4x-3)