equation in slope intercept form

Question

A car is worth $16,500 when it is three years old and $12,000 when it is six years old. Construct the equation in slope intercept form that represents the cost of a rental car. 

Answer 1

The given information translates into these two points: (3, 16500) (6, 12000) where each pair of coordinates is of the form (age-in-years, value-in-dollars).

 

From two points you can calculate slope (even though these y values are a bit larger than in some equations).

Then you can use Point Slope form to obtain an equation, which can easily be put into slope intercept form ("solve for y").