[tex]a)M_g=\sqrt{2\sqrt{5}\cdot10\sqrt{5}}=\sqrt{20\cdot 5}=10 \\
b)M_g=\sqrt{6\sqrt{3}\cdot 8 \sqrt{3}}=\sqrt{48 \cdot 3}=12\\
c)M_g=\sqrt{(2\sqrt{5}-\sqrt{14})\cdot(8\sqrt{5}-4\sqrt{14})}=\\
=\sqrt{(2\sqrt{5}-\sqrt{14})\cdot4(2\sqrt{5}-\sqrt{14})}=\\
=\sqrt{[(2\sqrt{5})^2-(\sqrt{14})^2]\cdot4}=\\
=\sqrt{(20-14)\cdot4}=\\
=2\sqrt{6}\\
d)M_g= \sqrt{ \frac{18}{5}\cdot \frac{1}{10} } = \sqrt{\frac{18}{50}} =\sqrt{ \frac{9}{25} }= \frac{3}{5} [/tex]