(X^10)(Y^-1)/(X^-5)(Y^5)I tried dividing coeficcients and then substracting exponents. It gave me (X^15)(Y^-6). This is almost right, but the...

When dealing with exponents, the convention is that an
expression is not simplified if it has negative exponents in
it.

So since `a^(-b) =
1/a^b`

The answer you got `x^15y^(-6)` is not fully
simplifed because it has a negative exponent.  Since `y^(-6) = 1/y^6` the equivalent
expression `x^15/y^6` is the correct answer because it does not have any negative
exponents.

I hope that helps.