A cube has a side length of x feet. which expression represents the surface area of the cube.

six sides ... each one x by x

The surface area of a cube is given by the formula:

\[
\text{{Surface Area}} = 6 \times (\text{{side length}})^2
\]

In this case, since the side length of the cube is x feet, the expression representing the surface area of the cube would be:

\[
6x^2
\]

To find the surface area of a cube, we need to sum up the areas of all six faces. Since a cube has six equal square faces, we can calculate the surface area by multiplying the area of one square face by six.

The area of a square face is determined by multiplying its length by its width. Since all sides of a cube are equal, the length and width of each square face are the same, denoted as x.

Therefore, the expression that represents the surface area of the cube is:

6 * (x * x) or 6x^2

In this expression, x^2 represents x squared, which is x multiplied by itself.

w.....wut?