Michelle has $12 and wants to buy a combination of dog food to feed at least three dogs at the animal shelter. A serving of dry food costs $1, and a serving of wet food costs $4. (please organize your answer)
Part A: Write the system of inequalities that models this scenario.
Part B: Describe the graph of the system of inequalities, including shading and the types of lines graphed. Provide a description of the solution set.