Answer: See explanation
Explanation:
Do you mean the greatest common factor (GCF), or the lowest common multiple (LCM).
If you mean GCF, then it is 1 because 7 is a prime number and has two facotrs (1 and itself) and since 9 isn’t divisible by 7, the GCF must be 1.
If you mean the LCM, the answer is 63. Using prime factorisation, we find the lowest prime factor of both numbers:
9 = 3^3
7= 7^1
Then, we multiply these together to give 63.
You cannot have a GCM, because you can’t find a greatest common multiple as numbers go on forever.
I hope this helps!