maths help please

to daviddem or some other mathemagician out there, please help me determine what is going on in this equation. this was provided to me by someone WITH all the processes done. it is designed to determine the EV of a 5bet shove (or more precisely, an unexploitable 5b shove range, hence EV is set to 0 - the worst hand in our shoving range has 0EV) i need to know what the processes were. i'll also outline what i think has been done with each step to help clarify for myself/to show that i actually tried.

here it is in its entirety before i break down what i think has happened. just so it reads a bit more fluently etc.

0 = F(36.5) + (1-F)(y)(-90) + (1-F)(1-y)(111.5)
0 = 36.5F + (1-F)(-90y) + (1 - F - y + Fy)(111.5)
0 = 36.5F - 90y + 90Fy + 111.5 - 111.5F - 111.5y + 111.5Fy
0 = -75F - 201.5y + 201.5Fy + 111.5
75F - 201.5Fy = -201.5y + 111.5
F(75 - 201.5y) = -201.5y + 111.5
F = (-201.5y + 111.5)/(75 - 201.5y)


and here's what i think's going on, and where i begin to have no idea what's going on.

0 = F(36.5) + (1-F)(y)(-90) + (1-F)(1-y)(111.5)

so this is just our starting equation. F is villain's fold percentage, and y is the equity of the worst hand in our shoving range.

0 = 36.5F + (1-F)(-90y) + (1 - F - y + Fy)(111.5)

so we've multiplied F by 36.5 to get 36.5F.
we have multiplied y by -90 to get (1-f)(-90y) in the middle bit
and we have then multiplied:
1 by 1,
-F by 1,
1 by -y,
and -F by -y to get:
(1 - F - y + Fy)

0 = 36.5F - 90y + 90Fy + 111.5 - 111.5F - 111.5y + 111.5Fy

here we have multiplied 1 by -90y and -F by -90y
also we have multiplied 1, -F, -y, and Fy by 111.5

0 = -75F - 201.5y + 201.5Fy + 111.5

here we have done:
36.5F - 111.5F
-90y - 111.y
90Fy + 111.5 Fy
it's at about this point that i get confused.

75F - 201.5Fy = -201.5y + 111.5

have we simply added 75F and subtracted 201.5Fy to/from both sides of the equation here? ie making sure the equation stays "balanced" or whatever the term is?

F(75 - 201.5y) = -201.5y + 111.5

no idea what's happened at this point.

F = (-201.5y + 111.5)/(75 - 201.5y)

no idea whats happened here because i need to know what happened in the last step.

any help appreciated.