Please help. Somebody give an answer to this question please. I need a step by step explanation as well.

ANSWER:
15d^2+7d-4

STEP BY STEP:
you can use F.O.I.L. to solve this (first,outer,inner,last)

first you multiply both of the first values in each set of parentheses, 5d and 3d to get 15d^2, then you multiply the terms on the outside, 5d and -1 to get -5d. then multiply the inner values, 4 and 3d to get 12d. because 12d and -5d are like terms, you combine them to get 7d. lastly, you multiply the last values in each parentheses, 4 and -1 to get -4

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.

Idon’t know what the answer is i wish i could