Answer:
Step-by-step explanation:
To find the GCF, we need to first determine ALL the factors of each of those numbers and then find the greatest common one among all 3 numbers.
42: 1, 2, 3, 6, 7, 14, 21, 42
75: 1, 3, 5, 15, 25, 75
90: 1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 90
The greatest common looks like it is 3. Not very great, but that's what it is.
