Answer:
-5y + 8x
Step-by-step explanation:
![(-4y-x)-(y-9x)\\\\-4y-x-(y-9x)\\\\\rightarrow-(y-9x)*-1=-y+9x\\\\-4y-x-y+9x\\\\-4y-y+9x-x\\\\\boxed{-5y+8x}](https://tex.z-dn.net/?f=%28-4y-x%29-%28y-9x%29%5C%5C%5C%5C-4y-x-%28y-9x%29%5C%5C%5C%5C%5Crightarrow-%28y-9x%29%2A-1%3D-y%2B9x%5C%5C%5C%5C-4y-x-y%2B9x%5C%5C%5C%5C-4y-y%2B9x-x%5C%5C%5C%5C%5Cboxed%7B-5y%2B8x%7D)
A hectare (ha) is the unit of area that can be used for that purpose.
It is roughly equivalent to 2.5 acres. It is equivalent in area to a square 100 m on a side. (10,000 m²).
Diameter is 6 so radius is 3, and the height is 3 times the radius = 9.
Volume is pi(3.14) * 3^2 * 9 = 254.34