# An MP3 player costs $70 and song downloads cost $0.85 each. How do you write an expression that represents the cost of the MP3 player and x number of downloaded songs. Then find the total cost if 20 songs are downloaded?

##### 2 Answers

The expression is

For

#### Explanation:

The $70 cost of the mp3 player is a fixed expense. We do not need a variable to express it.

The amount spent on music downloads depends on the number of songs we buy, so we use a variable to represent this number, and multiply that variable by the cost of each song.

Add the two terms, and you have the total cost.

See the solution process below:

#### Explanation:

The expression for the Total Cost of Ownership for this MP3 player is:

Substituting gives: