\[\begin{array}{l}
A = \frac{1}{{{\rm{x}} + \sqrt {\rm{x}} }} + \frac{{2\sqrt x }}{{x - 1}} - \frac{1}{{x - \sqrt x }}\;\\
\left( {x > 0;x \ne 1} \right)\\
= \frac{1}{{\sqrt x \left( {\sqrt x + 1} \right)}} - \frac{{2\sqrt x }}{{\left( {\sqrt x - 1} \right)\left( {\sqrt x + 1} \right)}} - \frac{1}{{\sqrt x \left( {\sqrt x - 1} \right)}}\\
= \frac{{\sqrt x - 1 - 2\sqrt x .\sqrt x - \left( {\sqrt x + 1} \right)}}{{\sqrt x \left( {\sqrt x + 1} \right)\left( {\sqrt x - 1} \right)}}\\
= \frac{{\sqrt x - 1 - 2x - \sqrt x - 1}}{{\sqrt x \left( {\sqrt x + 1} \right)\left( {\sqrt x - 1} \right)}}\\
= \frac{{ - 2x - 2}}{{\sqrt x \left( {\sqrt x + 1} \right)\left( {\sqrt x - 1} \right)}}\\
B = \left( {2 - \sqrt 3 } \right)\sqrt {26 + 15\sqrt 3 } \; - \;(2 - \sqrt {3)} \;\sqrt {26 - 15\sqrt 3 } \\
= \frac{1}{{\sqrt 2 }}[\left( {2 - \sqrt 3 } \right)\sqrt {52 + 30\sqrt 3 } - \left( {2 - \sqrt 3 } \right)\sqrt {52 - 30\sqrt 3 } ]\\
= \frac{1}{{\sqrt 2 }}.\left( {2 - \sqrt 3 } \right)\left( {\sqrt {27 + 30\sqrt 3 + 25} - \sqrt {27 - 30\sqrt 3 + 25} } \right)\\
= \frac{1}{{\sqrt 2 }}.\left( {2 - \sqrt 3 } \right)\left( {\sqrt {{{\left( {3\sqrt 3 + 5} \right)}^2}} - \sqrt {{{\left( {3\sqrt 3 - 5} \right)}^2}} } \right)\\
= \frac{1}{{\sqrt 2 }}\left( {2 - \sqrt 3 } \right)\left( {|3\sqrt 3 + 5| - |3\sqrt 3 - 5|} \right)\\
= \frac{1}{{\sqrt 2 }}\left( {2 - \sqrt 3 } \right)\left( {3 + \sqrt 3 + 5 - 3\sqrt 3 + 5} \right)\\
= \frac{1}{{\sqrt 2 }}\left( {2 - \sqrt 3 } \right).10\\
= 5\sqrt 2 \left( {2 - \sqrt 3 } \right)\\
= 10\sqrt 2 - 5\sqrt 6
\end{array}\]