Juan purchased a car for $20,000. If the car depreciates at a rate of 16% each year, what will be the value of his car after 3 years? First determine the equation needed to represent this situation and then determine the value. Make sure you select two answers.

1. For the total length of the two sides, you have to add the two polynomials together:


We can just combine like terms and we have our


2. We can set it up as:


All we need to do is subtract the polynomials to solve for y:


Simplify (subtract like terms):


That's the length of the 3rd side!

3. Yes, you can say that polynomials are closed under addition and subtraction based on Part A and Part B because whenever you add/subtract polynomials, you get an element from the same set. Indeed, they are 'closed'. 

Hope my answer helped! :)