Answer:
1
Explanation:
To find the greatest common factor (GCF) of 40, 43, and 21, you can first factor each number into its prime factors:
- The prime factorization of 40 is 2^3 x 5.
- The prime factorization of 43 is a prime number itself: 43 is prime.
- The prime factorization of 21 is 3 x 7.
Now, to find the GCF, you take the common prime factors with the lowest exponent:
GCF (40, 43, 21) = 2^0 x 3^0 x 5^0 x 7^0 = 1.
Therefore, the greatest common factor of 40, 43, and 21 is 1.