Agas station charges $2.19 per gallon of gas. use function notation to describe the relationship between the total cost c(g) and the number of gallons purchased

For this case, the first thing we must do is define a variable:
 g: number of gallons of gas.
 c (g): total cost.
 We then have a linear function of the form:
 c (g) = 2.19 * g
 
 A function notation to describe the relationship between the total cost c (g) and the number of gallons purchased is:
 c (g) = 2.19 * g