Question

You're DVD membership costs $16 per month for 10 DVD rentals. Each additional DVD rental is $2

Answer 1

a)
`y=2x-4`

b) independent variable: x - number of DVDs rented

dependent variable: y - the monthly cost of rent of x DVDs

c) $26

Explanation:

Question:

Your DVD membership costs $16 per month for 10 DVD rentals. Each additional DVD rental is $2.

a. Write an equation in two variables that represents the monthly cost of your DVD rentals.

b. Identify the independent and dependent variables.

c. How much does it cost to rent 15 DVDs in one month?

Solution:

Let x be the number of DVDs rented, and y be the monthly cost of rent of x DVDs.

a) For the first 10 DVDs you should pay $16 and for the next (x - 10) DVDs you have to pay additional $2 per DVD.

Then the total cost is

`y=16+2(x-10)\\ \\y=16+2x-20\\ \\y=2x-4`

b) Independent variable is x, dependent variable is y (the cost depends on number of DVDs rented).

c) If x = 15, then

`y=2\cdot 15-4=30-4=26`

It will cost $26 to rent 15 DVDs.