-21 , 4

Find the common factors for the numerical part:

-21,4

The factors for -21 are all numbers between 1 and 21, which divide -21 evenly.

Check numbers between 1 and 21

Find the factor pairs of -21 where x⋅y=-21.

List the factors for -21.

-21,-7,-3,-1,1,3,7,21

-21,-7,-3,-1,1,3,7,21

The factors for 4 are all numbers between 1 and 4, which divide 4 evenly.

Check numbers between 1 and 4

Find the factor pairs of 4 where x⋅y=4.

xy1422

List the factors for 4.

1,2,4

1,2,4

List all the factors for -21,4 to find the common factors.

-21: -21,-7,-3,-1,1,3,7,21

4: 1,2,4

The common factors for -21,4 are 1.

1

The GCF (HCF) of the numerical factors 1 is 1.

1

Find the GCF -21 , 4