The equation v=-2000+20000 describes the value in dollars of a certain model of car after it is t years old. If a car is worth $10,000, substitute 10,000 into the equation to find the age of the car.

I'm assuming the equation is:

v = - 2000t + 20,000 because the value of a car decreases with time

v = worth of the car

t = number of years

Since you know the value of v = 10,000, substitute or plug in 10,000 for v in order to find t

v = - 2000t + 20,000 Substitute 10,000 into v [To find t, you need to get the variable by itself to one side of the equation.]

10,000 = - 2000t + 20,000 Subtract 20,000 on both sides

-10,000 = - 2000t Divide - 2000 on both sides to get t by itself [negative divided by a negative results in a positive]

5 = t