Question

If x2 = 4, then x = 2. What is wrong with the argument?

Answer 1

are we assuming that this is x^2?

Answer 2

just plug it in

Answer 3

if by x2 you mean x^2,
-2^2 and 2^2 both equal to 4
so x is an arbitrary value

Answer 4

arbitrary isn't the best choice of words but yes it can be -2 or 2