Someone answered a post of mine earlier...i think it was CPhill's answer? Anyways, (I may be mistaken, if so SORRY CPHILL) this is what my instructor wrote... :

Thank you Nataszaa for ur points!a point for u from me too!

Sorry....I always forget about that, Nataszaa....I always assume the variables are positive, but I shouldn't!!! ......Your instuctor is correct!!!

To see why this is, suppose we have:

√(a²)  where "a" is negative.......If we evaluate this as just "a," we will get a negative value out of a positive square root, which is impossible!!!....

So the correct thing is......... l a l

Thanks for reminding me about this.....I'll have to put this one in my "memory bank" so I don't repeat that error!!!   

No sunglasses for this one!!!

i think becoz many people including me have borrowed ur sunglasses!

Yeah, rosala.......kitty<3 has "borrowed" a lot of them from me, too!!!!!!

That's OK........I have an endless supply!!

See???

Good then!becoz u dont seem happy without those sunglasses!

Youre welcome! Anytime! Could you solve my latest post about roots and radicals?

im sorry not studied that yet!

but i wish u luck!