a concession stand vendor counts the money in the register. after 1 h, it has $42.75. after 5 h, it has $260.75. how much money will be in the register at the end of an 8-hour shift

A concession stand vendor counts the money in the register.
 => 1 h, it has $42.75. 
=> 5 h, it has $260.75. 
260.75 - 42.75 = 218 are added to the money after 4 hours
=> 218 / 4 hours = 54.5 per hour
=> 54.5 * 3 additional hours = 163.5
=> 163.5+260.75=424.25
Hope this will help you!

The linear equation is: y=ax+b