X stands for the score of her first test
Y stands for the score of her second test
For the experimental probability you must record the data that you collect by flipping your own coin, then you must find the probability of landing on either side. For example, the theoretical probability for the coin toss it will be 50% chance for either side. For the experimental it depends on your own results.
The answer is 3 because since b=-5 you get -5 and add it to 14 giving you 9 and then you divide 9/3 which gives you 3. Hope this helps :)
Graph A
it shows two points for each x, meaning its not a function.