Greatest common factor of 8a and 18a

8a = 2 * 2 * 2 * a

18a = 2 * 3 * 3 * a

2 and a are common factors, therefore the GCM of 8a and 18a is 2a.

Ignore the a and add it at the end, because we know that both 8a and 18a are divisible by a

factors of 8:

1

8

4

2

factors of 18:

1

18

2

9

3

6

the highest number that both of them have in common is 2, so the GCF of 8a and 18a is 2a