Question

\(Phân - tích -thành -nhân -tử\\x + y -9 - \sqrt{xy}\)

Answer 1

\(Sửa:x+y-9-2\sqrt{xy}\\ =\left(\sqrt{x}-\sqrt{y}\right)^2-9=\left(\sqrt{x}-\sqrt{y}-3\right)\left(\sqrt{x}-\sqrt{y}+3\right)\)