In 2007, there were more than 8.14 million cars for sale. The number of cars then decreased by 23% per year. Write an exponential growth or decay model given by the number of c cars over t years after 2007. Use this model to estimate how many cars there were in 2013?

In 2013 there were approximately 2.2 million cars for sale.

Step-by-step explanation:

Since the number of cars is decreasing by 23% per year, it is a decay model. This types of decay can be expressed in the following expression:

Where x is the year, cars(2007) is the number of cars in 2007. Applying this data we have:

If we want to know the number of cars in 2013, we need to apply that value to x and solve the expression.

In 2013 there were approximately 2.2 million cars for sale.

-7

step-by-step explanation:

x^2 + 18x + 74 = (x + 9)^2 - 81 + 74

= (x + 9)^2 - 7.

so q = -7.

4.08%

step-by-step explanation: