Solve for the value of T

The random variable x represents the number of phone calls an author receives in a day, and it has a poisson distribution with a mean of 8.7 calls. what are the possible values of x

Can you me with this question? i'll reward *30 points i just need with this one question so that i could solve the others. * edit: i originally set up the question to reward 30 points, but for some reason i can only reward 15. if you don't get 30, then i'm sorry. i'm still kind of new to this site

Your friend, taylor, missed class today and needs some identifying solutions to systems. explain to taylor how to find the solution(s) of any system using its graph.