Đáp án:
$\begin{array}{l}
1)\left( {\dfrac{{\sqrt 6 - \sqrt 2 }}{{1 - \sqrt 3 }}} \right) - \dfrac{5}{{\sqrt 5 }}:\dfrac{1}{{\sqrt 5 - \sqrt 2 }}\\
= \dfrac{{ - \sqrt 2 \left( {1 - \sqrt 3 } \right)}}{{1 - \sqrt 3 }} - \sqrt 5 .\left( {\sqrt 5 - \sqrt 2 } \right)\\
= - \sqrt 2 - 5 + \sqrt {10} \\
= \sqrt {10} - 5 - \sqrt 2 \\
B2)7.\sqrt {{{\left( { - 2} \right)}^2}} - \dfrac{3}{{10}}.\sqrt {{{\left( { - 5} \right)}^2}} - 2\sqrt {{3^2}} \\
= 7.\sqrt 4 - \dfrac{3}{{10}}\sqrt {25} - 2\sqrt 9 \\
= 7.2 - \dfrac{3}{{10}}.5 - 2.3\\
= 14 - \dfrac{3}{2} - 6\\
= 8 - \dfrac{3}{2}\\
= \dfrac{{13}}{2}
\end{array}$