Step-by-step explanation:
x^3 is a perfect cube, 8 is a perfect cube, so we use difference of cubes.

Cube root of x^3 is x.
Cube root of 8 is 2
So
a=x
b= 2.

Set these equations equal to zero



If we do the discriminant, we get a negative answer so we would have two imaginary solutions,
Thus the only real root is 2.
If you want imaginary solutions, apply the quadratic formula.

and

This is not middle school work
Since there are 2 sides to the shelf, there is 0.05*2=0.05+0.05=0.1 meters of space between the shelf and wall in total. Next, since each piece of wood is 0.3 meters wide and we have 3 of them, the total width of the wood is 0.3+0.3+<something>
Note that <width of wood>+<space between shelf and well> =width of closet
I challenge you to finish this on your own - good luck, and feel free to ask with any further questions!
<span>False. Perimeter is a linear measure. Square units are for area.</span>