Create a cool looking math equation for my marketing class -- 2

Hi, I'd like to create a math equation which create a number of variables to show how difficult a specific marketing solution can be. I want it to look very "academic" in order to hold the attention of my students, but be simple enough to understand with college/MBA level math. Variables: # of corporate email marketing solutions Cost of technology ($0-500/month, 501-1000, 1000+ Quality of content (1-10) Quantity of content (1-140 characters, 141-500, 501+) Number of content posts per week (1-7) Time spent per week creating content (1-3 hrs, 3-5, 5-10) Cost of email design ($1-50, 50-150, 151+) Goal of equation: show that email marketing will fail for most companies due to the cost and complexity to create great content to "feed the email marketing machine"