A vendor sells silk-screened T-shirts at community festivals and craft fairs. The costs incurred in the production and sale of the shirts are $90 plus $3.50 for each shirt sold and the vendor sells them for $9 each.a) Write the revenue, cost, and profit functions the model this situation.b) How many T-shirts must the vendor sell in order to break even?c) Find and interpret the slope of the profit function.