Question: what is the greatest common factor of 49 and 84?
Answer: The prime factorization of 49 is: 7 x 7.
The prime factorization of 84 is: 2 x 2 x 3 x 7.
The prime factors and multiplicities 49 and 84 have in common are: 7.
7 is the gcf of 49 and 84.
gcf(49,84) = 7.