Renata wins a $20 gift card to an online music site. after renata purchases 16 songs, the gift card has a remaining balance of $0. which equation represents the relationship between y, the remaining balance on renata’s gift card, and x, the number of songs purchased?

$20 bought 16 songs
Therefore each song costs $20/16 = $5/4 = $1.25
So:
2 songs would cost 2 * $1.25
3 songs would cost 3 * $1.25
...
x songs would cost x * $1.25

Since Renata started with $20, then her balance (y) after buying x songs would be:

y = 20 - 1.25*x

First step is to get rid of the square root. remember that a square root is the same as raising to the (1/2) power. see below: multiply exponents per exponent rules to get: remember you subtract exponents from the denominator and add exponents in the numerator so: simplify further: so a is the correct choice. if you don't understand this google exponent rules and it will you understand. look at the image results.