The domain is (0,-5) and range is (0,-7) the y is the range and the x is the domain
The square of a binomial expands as follows:

Expanding all the binomials, we have

Sum like terms:

Simplify terms appearing on both sides:

Move all terms involving k to the left and all numbers to the right:

Divide both sides by -20:

You’re answer would be x=18.28
Since they expect to put 16 songs, but actually end up putting 50% more, we can do 16 * 150 % which would equal 24 songs that they actually put on their CD.
During the editing process, they removed 75 % of the songs they put on their CD. Since they put 24 songs on their CD, we can do:
24 * 25 % (because this would equal the songs left after the editing process, and not the actual number of songs removed, which is 75 %) which would equal 6 songs.
There would be 6 songs left on their Final CD.