Answer:
8 in
Step-by-step explanation:
since the box is the same length in all sides, it is a cube.
length, width and height are all the same.
the volume is 512 in³.
and the volume of a cube is length×width×height = side length³.
512 = length³
length = 8 = width = height
Perimeter Formula:

Area Formula:

Set perimeter Formula equal to b:

Plug formula for be we just made above into the area Formula:

Solve for L (you'll have to use quadratic formula) then plug that back into the area Equation and solve for b.
Here's a link to where the problem has been explained before (they go into more detail than me).
https://brainly.ph/question/468631
lmk if you need any more help
Answer:
4x+1
Step-by-step explanation:
The area is 12x2 + 3x in
The length is 3x
Formula is A=L*B
12x2 + 3x=3x*B
Divide both side by 3x
12x2+3x divide by 3x=B
4x+1=B
The express for the width is 4x+1
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