Final answer:
To answer the student's question about car value depreciation, an equation V = P - 4000x was established, which models the car's value decrease of $4,000 yearly. After 3 years, when the car's worth was $18,000, the original value was calculated to be $30,000.
Step-by-step explanation:
To solve the student's question regarding the depreciation of a car's value, we need to establish an equation that expresses the value V of the car x years after it is purchased, given that the car decreases in value by $4,000 each year.
Part A: Write the Equation
The general form for the equation that models this depreciation is:
V = P - 4000x
Where:
V is the value of the car x years after purchase,
P is the original value of the car,
And 4000x represents the total depreciation after x years.
Part B: Original Value of the Car
Using the information provided that after 3 years the car is worth $18,000, we plug in the values:
18000 = P - 4000(3)
This reduces to:
18000 = P - 12000
Adding 12000 to both sides:
P = 18000 + 12000
P = $30,000
The original value of the car was $30,000.