help please

Alex will make and sell tie-dye sweatshirts at a fair. The fixed costs for making the sweatshirts and securing a booth at the fair is 800 dollars. It also costs Alex 12 dollars to purchase and tie-dye each sweatshirt. Previous experience suggests that if Alex sets the price at 40 dollars, 100 sweatshirts will sell. For each 1 dollar of price decrease, 5 more sweatshirts will sell, while for each 1 dollar of price increase, 5 less will sell. Let be the price of one sweatshirt. What is the profit? O-(100 - 12.x) - 800 -Sr? +400x - 4400 40 - 800 OS? - 300 - 4000 0-42? + 300 - 4000 -5 + 360 - 4400