Cho \( A = \left( {{{x – y} \over {\sqrt x – \sqrt y }} + {{\sqrt {{x^3}} – \sqrt {{y^3}} } \over {y – x}}} \right):{{{{\left( {\sqrt x – \sqrt y } \right)}^2} + \sqrt {xy} } \over {\sqrt x + \sqrt y }}\) Với \( x \ge 0, \, y \ge 0,x \ne y.\) a) Rút gọn \(
Cho \( A = \left( {{{x – y} \over {\sqrt x – \sqrt y }} + {{\sqrt {{x^3}} – \sqrt {{y^3}} } \over {y – …