Answer:
2
Step-by-step explanation:
The factors of 8 are: 1, 2, 4, 8
The factors of 42 are: 1, 2, 3, 6, 7, 14, 21, 42
The factors of 90 are: 1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 90
Then the greatest common factor is 2.
