bai nay lam sao rut gon chi phan tich thanh nhan tu duoc thoi
x√x+y√y+x-y=
\[\begin{array}{l}
(\sqrt x + \sqrt y )(x - \sqrt {xy} + y) + (\sqrt x + \sqrt y )(\sqrt x - \sqrt y )\\
= (\sqrt x + \sqrt y )(x - \sqrt {xy} + y + \sqrt x - \sqrt y )
\end{array}\]