Luke is keeping track of the total number of hours he exercises. He started the summer having already put in 15 hours, and he then exercises 7 hours each week. The function to keep track of his exercise is f(x) = 7x + 15. What do the f(x) and x represent in Luke's situation?
x is number of weeks
f(x) is total number of hours
In Luke's situation, the function f(x) represents the total number of hours he has exercised, and x represents the number of weeks since he started keeping track.
The expression 7x represents the number of hours Luke exercises in each week, because he exercises for 7 hours per week. And since he already had 15 hours before the summer started, the expression 7x + 15 gives the total number of hours he has exercised at any given week x.
So, if you were to plug in a specific value for x into the function f(x) = 7x + 15, you would get the total number of hours Luke has exercised after that number of weeks.