In a certain region, the equation  yˆ=19.485x+86.912  models the amount of a homeowner’s water bill, in dollars, where x is the number of residents in the home.
 What does the slope of the equation represent in context of the situation?
The water bill increases by about $87 every month.
The water bill increases by about $87 for every additional resident in the home.  The water bill increases by about $19 for every additional resident in the home.  The water bill increases by about $19 every month.