Help please mathematics

The roots of the function f(x) = x2 – 2x – 3 are shown. what is the missing number?

Me its important ! marge runs an ice cream parlor. her speciality is triple chocolate sundaes.she can prepare 1 sundae every 2 minutes, and she earns $1.20 for each sundae she makes . if she just makes sundaes for a single shift of at most 4 hours and at least 2 hours , which function relates her earnings to the number of minutes she works?

Jennifer is 20 miles north of her house, and she is driving north on the highway at a rate of 55 miles per hour whats the slpoe