Đáp án:
\(\begin{array}{l}
a)P = - \dfrac{{\sqrt 6 }}{3}\\
b)Q = 3
\end{array}\)
Giải thích các bước giải:
\(\begin{array}{l}
a)P = \dfrac{{2.2\sqrt 2 - 2\sqrt 3 }}{{3\sqrt 2 - 4\sqrt 3 }}\\
= \dfrac{{4\sqrt 2 - 2\sqrt 3 }}{{3\sqrt 2 - 4\sqrt 3 }}\\
= \dfrac{{2\left( {2\sqrt 2 - \sqrt 3 } \right)}}{{\sqrt 6 \left( {\sqrt 3 - 2\sqrt 2 } \right)}}\\
= - \dfrac{{2\left( {2\sqrt 2 - \sqrt 3 } \right)}}{{\sqrt 6 \left( {2\sqrt 2 - \sqrt 3 } \right)}}\\
= - \dfrac{2}{{\sqrt 6 }} = - \dfrac{{2\sqrt 6 }}{6} = - \dfrac{{\sqrt 6 }}{3}\\
b)Q = \dfrac{{\sqrt 3 \left( {\sqrt 3 + 2} \right)}}{{\sqrt 3 }} + \dfrac{{\sqrt 2 \left( {\sqrt 2 + 1} \right)}}{{\sqrt 2 + 1}} - \sqrt 2 - \sqrt 3 \\
= \sqrt 3 + 2 + \sqrt 2 + 1 - \sqrt 2 - \sqrt 3 \\
= 3
\end{array}\)