Answer:
The required formula for y, the number of cars sold is:
.
Step-by-step explanation:
Consider the provided information.
Let x represents the amount of money spend on advertising
.
y is number of cars sold,
For each additional 5000 dollars spent, they sold 40 more cars.

The y-intercept form is: 
Substitute x=60,000, y=680 and m=0.008 in the above equation.



Thus, the required formula for y, the number of cars sold is:
.