Verified answer

-1≤-4x+12≤1

-12 from left, middle, right

-13≤-4x≤-11

divide all by -4 (this will change all the signs and I copied/paste your sign and can't type a greater to or equal sign..so I'll just type >)

13/4>x>11/4

interval notation

[11/4,13/4]

rewrite as | 4x - 12| ≤ 1 if and only if -1 ≤ 4x -12 ≤ 1---> 11 ≤ 4x ≤ 13

or 11/ 4 ≤ x ≤ 13/4---> [ 11/4 , 13/4]

The gist of the communicate accessible (sorry, there are too many pages to grant all the links) is that wands help to concentration the magic resident interior the witch or wizard, yet wandless magic remains conceivable, extremely for extremely proficient human beings like Snape and Dumbledore. some examples ... Apparition Assuming one's Animagus kind (or Metamorphpagus) Accio (the Summoning charm) Elves can do magic without employing wands Lumos

[11/4, 13/4]