How do i solve this when using the foil method (5r+13)(r+2)

Firstly, you have to know what FOIL stands for.
F= first
O= outside
I= inside
L= last

So to solve you start with the first two numbers of each of the equations in parentheses (5r and r) which will equal 5r^2 

outside is 5r and 2 which equals 10r

inside is 13 and r which equals 13r

last is 13 and 2 which is 26

then you have 5r^2, 10r, 13r, and 26

add common characters and you'll have 5r^2+23r+26

40 because it’s just a little longer than 32 feet

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.