The faces of a rectangular solid are square.
always
sometimes
never

The faces of a rectangular solid are sometimes square.

Step-by-step explanation:

We can consider the example of a cuboid.

It is a rectangular solid whose all faces are made of rectangles.

But if we will consider a example of cube; which is also a kind of rectangular solid whose all faces are made up of square.

so we can get some solids whose faces are other than squares as well and some whose faces are squares.

Hence, we could say that:

The faces of a rectangular solid are sometimes square.

step-by-step explanation:

to determine whether a given function is even, we simply substitute x with -x in the expression. if the result after simplification is identical to the original equation, then the function is said to be even other wise odd.

f(-x) = (-x)^2 - (-x) + 8

      = x^2 + x +8

the resulting function is not identical to the original one;

f(-x) ≠ f(x)

therefore, f(x) is not an even function