Đề bài

Rút gọn :

a) $\dfrac{{3 + 2\sqrt 3 }}{{\sqrt 3 }} - \dfrac{{2\sqrt 3  + \sqrt {15} }}{{\sqrt 5  + 2}}$;

b) $\dfrac{{5\sqrt 2  - 2\sqrt 5 }}{{\sqrt {10} }} - \dfrac{3}{{\sqrt 5  - \sqrt 2 }}$;

c) $\dfrac{{\sqrt {15}  - \sqrt {12} }}{{\sqrt 5  - 2}} - \dfrac{1}{{2 - \sqrt 3 }}$; 

d) $\dfrac{4}{{1 + \sqrt 3 }} + \dfrac{{\sqrt 3  - 1}}{{\sqrt 3  + 1}}$;

e) $\sqrt {4 - 2\sqrt 3 }  + \sqrt {\dfrac{2}{{2 - \sqrt 3 }}}  - \sqrt {27}$; 

f) $\dfrac{{\sqrt 2 }}{{\sqrt {\sqrt 2  + 1}  - 1}} - \dfrac{{\sqrt 2 }}{{\sqrt {\sqrt 2  + 1}  + 1}}$.