Why is #sqrt(-2) sqrt(-3) != sqrt((-2) * (-3))# ?
Here's another example:
#1 = sqrt(1) = sqrt((-1)*(-1)) != sqrt(-1)*sqrt(-1) = -1#
This kind of thing happens because every non-zero number has two square roots and the one we mean when we write
So long as you stick to
#sqrt(ab) = sqrt(a)sqrt(b)#
When you get to deal with complex numbers more fully (in precalculus?) then it may become clearer.