The GCF of 75 and 105 is 15. This leaves you with 5 and 7 respectively after division. You can do nothing further.
The GCF is 21.
The GCF is 5.
The GCF is 5.
The GCF is 21.
The GCF is 7.
The GCF is 75.
If you mean 300 and 450 then the GCF is 150
The GCF is 75.
The GCF is 75.
The GCF is 75.
The GCF is 75.
The GCF is 75.