Step-by-step explanation:
Part A:
So the height is going to be x when you fold the sides up. So that's one part of the volume but for the width it was going to be 4 but since two corners were cut out with the length x the new width is going to be (4-2x). The same thing applies for the length which should be 8 inches but since two corners were removed with the length x it's now (8-2x)
v = x(4-2x)(8-2x)
Part B:
The volume can be graphed although there must be a domain restriction since the height, width, or length cannot be negative. So let's look at each part of the equation
so for the x in front it must be greater than 0 to make sense
for the (4-2x), the x must be less than 2 or else the width is negative.
for the (8-2x) the x must be less than 4 or else the length is negative
so the domain is going to be restricted to 0 < x < 2 so all the dimensions are greater than 0
By using a graphing calculator you can see the maximum of the given equation with the domain restrictions is 0.845 which gives a volume of 12.317