Need help with algebra

Question

Joe buys a car for $5,000. Every year, it depreciates 10%. That means it is worth 90% of what it was worth the year before. If x = # of months after Joe bought the car, and y = value in dollars of the car, write an exponential equation that models this function. Hint: Here are a few points on the graph: (1, 4500), (2, 4050), (3, 3645) (4, 3280.50).

The absolute value of b in y = a(b)^x was less than 1. Instead of depreciating by 10%, write an equation that would model the value of the car if it appreciated by 10%, and state what the car would be worth in 5 years.

Answer 1

This problem is NOT simple. I suggest that you ask your teacher about year and month.

Every year, it depreciates 10%.~~~~~~~~~~~~~~unit here is year.

If x = # of months~~~~~~~~~~~~~~~~~~~~~~~~~unit here is month.

y = a(b)^x~~~~~~~~~~~~~~~~~~~they ask you to use this, and gave you a few points. In order to get all those given point and use y = a(b)^x, the x must be # of year.

Given a few points on the graph: (1, 4500), (2, 4050), (3, 3645) (4, 3280.50).

Think about it, after 1 year car worth 4500 from 5000? it is NOT realistic.

if it is 1 month, then given points are realistic, in this case rate should be 10% every month. But it says every year.

Something is wrong with this problem in my opinion.

please check with your teacher and get the problem correct. I would like to see correct problem. Thanks!

Please, give me sum up if you like it.

          give me sum down if you do not like it.

           give me explanation if I am wrong.

           give me any comments regarding my answers.

Thanks!

Answer 2

Since, after one year of depreciation, the car is worth 90% of what it was the year before:

y = 5000•(0.9)^x

Likewise, after one year of appreciation, the car is worth 110% of what it was the year before:

y = 5000•(1.1)^x

Answer 3

As it states last, the absolute value is less than 1 and so it will go down. (0.9<1) If instead of subtracting 0.1 from 1 we added, we'd get a value of 1.1 and the equation would be y=5,000(1.1)^x where x is the number of years the car is owned. The value would then be $8,055.55