Roots of nth? Confused!

[Guest]

Hi,

So I have this problem to simplify:

So I think that the roots are even and the power is odd, so I absolute value x and y and I get this:

But according to the book answers, the real answer is:

How can that be?

Thanks

 

[stapel]

Your answer is correct, assuming there is no restriction on x and y. But many (most?) books work under the assumption (sometimes not stated) that all variables indicate non-negative values.

The format of the book's answer makes me think that it is working under that assumption. Ask your instructor, though, to be on the safe side.

Eliz.