The sum of two consecutive integers is 57.

if x is the first integer, write and solve an equation to determine both numbers.

what are the two numbers?

If the first integer is x, the second integer must be (x+1) since you know they are consecutive. So you can write:
 
x+(x+1)=57
2x+1=57
2x=56
x = 28 and x+1=29

28+29=57.

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.