How do you 31? i don't understand how too

Consider the function f(x)=-5x+3 what is f(-2)

The map shows the location of the airport and a warehouse in a city. though not displayed on the map, there is also a factory 112 miles due north of the warehouse. a truck traveled from the warehouse to the airport and then to the factory. what is the total number of miles the truck traveled?

Apackage of five erasers cost 0. $.39 at this rate how many how much would 60 erasers cost in dollars and cents