What's - x if x is - 4? is it 4 or - 4?

If x = - 4, then - x = 4.

Step-by-step explanation:

The procedure for answering this question is straightforward, you just have to substitute the value of x, when you write - x:

If x = - 4, then - x = - (-4) = 4 (remember the law of signs)

Therefore: - x = 4.

It actually holds for any real number.