Why can you write a subtraction problem as an addition problem? how do you write a subtraction problem as an addition problem?

The cost to rent a moving truck is a flat fee of $25 plus $0.60 per mile. the equation c = 25 + 0.6m models the cost, c, in dollars for the number of miles, m, traveled in the truck. identify the independent and dependent variables. the is the independent variable. the is the dependent variable.