Final answer:
The luxury car will take 25 years to totally depreciate.
Step-by-step explanation:
The straight line depreciation equation for a luxury car is y = -3,400x + 85,000. To find the number of years it will take for the car to totally depreciate, we need to determine the value of x when y equals zero since total depreciation occurs when the value of the car is zero. Setting y equal to zero and solving for x:
0 = -3,400x + 85,000
3,400x = 85,000
x = 85,000 / 3,400
x = 25
Therefore, it will take 25 years for the luxury car to totally depreciate.