An open box is to be made from a flat piece of material 9 inches long and 4 inches wide by cutting equal squares of length $x$ from the corners and folding up the sides.

Write the volume $V$ of the box as a function of $x$. Leave it as a product of factors, do not multiply out the factors.
$V(x) =$

If we write the domain of $V(x)$ as an open interval in the form $(a,b)$, then what is $a$?
$a =$
and what is $b$?
$b =$