In the absence of any equality signs and proper grammar with great difficulty if not impossible.
Lets start by putting the known number on the other side. Y3 -7500y=125000. There is your start. Take it from here.
No, because it is not an equation (or inequality), but simply two expressions separated by a space.
16y3 / 20y4 = 16/20 * y3/y4 = 4/5 * y3-4 = 4/5 * y-1 or 4/5y
6y-y3 = 3
You would need to know the value of either x or y, so that you could solve for the one independent variable.
-y3 + 7y3
x3-y3
y3 + 9y + 10y - 5/y + 2 can not be solved, as it is not an equation. If you would like to simplify it, you can reduce it a bit: = y3+ 19y - 5/y + 2
72
27-y3 factored completely = 24
X2+Y3+15 All you can do is simplify it.