I wanted to know if I can square a negative number..?
Yes, you can square a negative number. In fact, any number at all can be squared, even numbers like pi and 0. This is because to square a number just means to multiply it by itself.
For example, (-2) squared is (-2)(-2) = 4. Note that this is positive because when you multiply two negative numbers you get a positive result.
You may be confused about whether you can square a negative number because what you can't do is take the square root of a negative number.
This is because if a negative number had a square root, you would have to find a number that when you multiply it by itself, the result would come out negative. This can't happen because either that number would be positive and a positive times a positive is positive, or that number would be negative and a negative times a negative is also positive.
Only a positive times a negative (or a negative times a positive) will result in a negative answer and then those numbers would not be the same (because they have different signs) and so they could not be square roots.
Hope this helps,