An open box is to be made from a flat piece of material 12 inches long and 3 inches wide by cutting equal squares of length 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= ??

Solution：

V(x)=(12-2x)(3-2x)x

a = 0

b = 1.5