If the range of the numbers in the list L is 4, then x can't be 4 since there is an element in the list that is x^2. Therefore,
0 ≤ x^2 ≤ 4 so that it would be the highest number and
0 ≤x ≤ 2
So, the value of x can be equal to 2 but not higher. So, 2 is always greater or equal to x.