One important thing to mention about square and square roots of a number is that square roots are always positive.
i.e. √4 = 2 only.
√4 ≠ (-2) because square roots are always positive.
Although if you find an equation like X² = 4, then X can be both 2 and -2 because squaring both 2 and -2 will result in 4.
One common mistake which should be avoided when you know this thing:
When you have X² = 4 .... (1)
We usually have our next step as X = √4 ..... (2)
and then we write X = 2 only.
This would have been true if the original equation was given as X = √4 but in this case when we square root both sides of eq (1) and so we eliminate the negative root which should be considered in the final answer.
Hence, here the answer will be X = 2, -2 ... (Ans)