Abcdegfdsajg12345 Abcdegfdsajg12345 28-08-2022 Mathematics contestada 5. A t-shirt shop is running a special. The first shirt costs $15, but each additional shirt is cheaper. The cost, c, for n t-shirts is given by the equation: c=15+9(n-1). a) What is the cost to purchase 3 t-shirts?