Normally you would say what number when multiplied by itself equals 9
Well 3 x 3 = 9 and (-3) x (-3) = 9 so why is it not
The reason is the √ operator or instruction means only the positive one so the first one is correct. There is more but it is jargon that you do not need right now.
That is the same thing but it is bit less clear. Although you understand it remember that math is language. Soon your mind will begin to utilize the rules of this language and you will speak it better and better. But because it is a language you must speak it to other people. Not only must you understand it they must understand it when you speak it to them.
Then get to know more people.
Perhaps in the past, one could lead a sheltered existence and only know of 50 -100 people. But this is the 21st century, the time of Armageddon. I personally know close to 40 million people thanks to the internet and so should you.
And by the way, Rafiqul Amin, I do not know him...
I never said that. Please read post #1.
As I have said many times I am not a math guy, I am a computational guy. Thusly, I stay away from dry math definitions of the type best left to the theoreticians whom are experts in such things.
But since this is the kind of post JFF would deliver at me my heart has experienced a warm feeling. For that I thank you.