Đề bài

Rút gọn biểu thức

a) $\left( {5\sqrt {\frac{1}{5}}  - \frac{1}{2}\sqrt {20}  + \sqrt 5 } \right)\sqrt 5$

b) $\left( {\sqrt {\frac{1}{7}}  - \sqrt {\frac{9}{7}}  + \sqrt 7 } \right):\sqrt 7$

c) ${\left( {\sqrt {\frac{2}{3}}  - \sqrt {\frac{3}{2}} } \right)^2}$

d) $\frac{{\sqrt {{{312}^2} - {{191}^2}} }}{{\sqrt {503} }}$

e) $\sqrt {27.{{\left( {1 - \sqrt 3 } \right)}^4}} :3\sqrt {15}$

g) $\frac{{\sqrt[3]{{135}}}}{{\sqrt[3]{5}}} - \sqrt[3]{{54}}.\sqrt[3]{4}$