Nadia has a $15 gift card to an online music store. Each song at the store costs $0.99. The equation m = 15 - 0.99s represents the amount of money, m, Nadia has left on the gift card after buying 5 songs. a.
The independent variable is b.
How does the amount of money left on the card change for each extra song Nadia buys?
Show your work. and the dependent variable is​