What two numbers add to 15 and multiplied to -100

Jackie purchased 3 bottles of water and 2 cups of coffee for a family for $7.35. brian bought 4 bottles of water and 1 cup of coffee for his family for $7.15. how much does each bottle of water cost? how much does each cup of coffee cost? i need this done

If i have a 24 in loaf of bread and i cut it into two pieces one 9 in how long was the other

Write an equation for the function that includes the points (2,100)and (3,100)