Answer:
3
Explanation:
GCF means greatest common factor. It is the largest number that 3, 15, and 9 are divisible by.
3 is divisible by only 1 and 3
15 is divisible by 1, 3, 5, and 15
9 is divisible by 1, 3, and 9
The largest number 3, 15, and 9 are divisible by is 3.
The GCF of 3, 15, and 9 is 3.