When you simplify each of those expressions you get 120xy, 210xy and 216xy. The GCF of those is 6xy because it divides evenly into all of them.
It is: 10
What is the Greatest common factor of 21 and 84
The GCF is 7.
The GCF is 3.
The GCF is 7.
infinite
6.
Common factors
It is 2
6
10
3k
3k
3
It is: 4
It is: 10
It is: 3