Answer:
The GCF is going to be 2
Explanation:
This Is how I find the GCF of 3 numbers. I find the prime factorization first, then I find the common factors and multiply them. Here
The prime factorization of 8, 2 × 2 × 2 = 8
The prime factorization of 18, 2 × 3 × 3 = 18
The prime factorization of 70, 2 × 5 × 7 = 70
The one and THE only common factor is 2, which is going to be the GCF