What is the greatest common factor for 84 and 56?

Factors of 56 are: 1, 2, 4, 7, 8, 14, 28, 56

Factors of 84 are: 1, 2, 3, 4, 6, 7, 12, 14, 21, 28, 42, 84

The outside term multiplies by the outside term on the oposite side to equal the answer. 

Example:
Look at the factors of 84
84X1=84
2X42=84
3X28=84 
and so on!

In all honesty, there really is no “work” per say to show. mainly it’s just using the process of elimination. the question is asking which domain(s) would be the most appropriate for the function c(n). n is the number of observed vehicles so right away, 1, 2, and 3 can be eliminated.why? 1, 2 start in the negatives and therefore it is impossible to observe negative cars. so, #4 would be the best answer to the given problem.