0 bình luận về “Rút gọn
A= (x + y)/ ( √x – √y) ² – 2/√xy : [ (1/
√x) – ( 1/ √y)]
mn giúp mk vs ạ”
Đáp án:
$\begin{array}{l} A = \dfrac{{x + y}}{{{{\left( {\sqrt x – \sqrt y } \right)}^2}}} – \dfrac{2}{{\sqrt {xy} }}:\left( {\dfrac{1}{{\sqrt x }} – \dfrac{1}{{\sqrt y }}} \right)\\ = \dfrac{{x + y}}{{{{\left( {\sqrt x – \sqrt y } \right)}^2}}} – \dfrac{2}{{\sqrt {xy} }}:\dfrac{{\sqrt y – \sqrt x }}{{\sqrt {xy} }}\\ = \dfrac{{x + y}}{{{{\left( {\sqrt x – \sqrt y } \right)}^2}}} + \dfrac{2}{{\sqrt {xy} }}.\dfrac{{\sqrt {xy} }}{{\sqrt x – \sqrt y }}\\ = \dfrac{{x + y}}{{{{\left( {\sqrt x – \sqrt y } \right)}^2}}} + \dfrac{2}{{\sqrt x – \sqrt y }}\\ = \dfrac{{x + y}}{{{{\left( {\sqrt x – \sqrt y } \right)}^2}}} + \dfrac{{2\left( {\sqrt x – \sqrt y } \right)}}{{{{\left( {\sqrt x – \sqrt y } \right)}^2}}}\\ = \dfrac{{x + y + 2\sqrt x – 2\sqrt y }}{{{{\left( {\sqrt x – \sqrt y } \right)}^2}}} \end{array}$
Đáp án:
$\begin{array}{l}
A = \dfrac{{x + y}}{{{{\left( {\sqrt x – \sqrt y } \right)}^2}}} – \dfrac{2}{{\sqrt {xy} }}:\left( {\dfrac{1}{{\sqrt x }} – \dfrac{1}{{\sqrt y }}} \right)\\
= \dfrac{{x + y}}{{{{\left( {\sqrt x – \sqrt y } \right)}^2}}} – \dfrac{2}{{\sqrt {xy} }}:\dfrac{{\sqrt y – \sqrt x }}{{\sqrt {xy} }}\\
= \dfrac{{x + y}}{{{{\left( {\sqrt x – \sqrt y } \right)}^2}}} + \dfrac{2}{{\sqrt {xy} }}.\dfrac{{\sqrt {xy} }}{{\sqrt x – \sqrt y }}\\
= \dfrac{{x + y}}{{{{\left( {\sqrt x – \sqrt y } \right)}^2}}} + \dfrac{2}{{\sqrt x – \sqrt y }}\\
= \dfrac{{x + y}}{{{{\left( {\sqrt x – \sqrt y } \right)}^2}}} + \dfrac{{2\left( {\sqrt x – \sqrt y } \right)}}{{{{\left( {\sqrt x – \sqrt y } \right)}^2}}}\\
= \dfrac{{x + y + 2\sqrt x – 2\sqrt y }}{{{{\left( {\sqrt x – \sqrt y } \right)}^2}}}
\end{array}$