Felipe subtract 3x from both side to get rid of x on one side. Ik this isn’t part of the answer but the correct way to do this would be to subtract 2x from each side after adding 8 to each side of the equation
Answer:
you didn't post a picture :/
$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