if the points (0,0,0),(4,0,0),(0,4,0),(0,0,4) are 4 vertices of a cube , then the equation of the sphere touches its faces from inside is​

-|x| means that the value of x will be negitive due to the negitive sign on the outside. But |-x| that has a negitive sigh inside and the two lines that are on the outside on the -x is to make the number inside positive. So the first one will be -x at the end. The second one will be just x