Question

$frac{x-y} sqrt{x} - sqrt{y}$

Answer 1

$frac{ (sqrt{x})^{2}-(sqrt{y})^{2} }{ sqrt{x} - sqrt{y}}= frac{(sqrt{x} - sqrt{y})(sqrt{x}+sqrt{y})}{sqrt{x} - sqrt{y}}=sqrt{x} + sqrt{y}$