Salut.
1.
[tex]=(\frac{3}{2\sqrt{3} }- \frac{3}{\sqrt{3}}+ \frac{9}{3\sqrt{3}} )-(\frac{12}{4\sqrt{3} }+ \frac{45}{5\sqrt{3}}+ \frac{3}{\sqrt{3}} )=\\=(\frac{3}{2\sqrt{3} }- \frac{3}{\sqrt{3}}+ \frac{3}{\sqrt{3}} )-(\frac{3}{\sqrt{3} }+ \frac{9}{\sqrt{3}}+ \frac{3}{\sqrt{3}} )=\\ =\frac{\sqrt{3} }{2}-(\frac{6}{\sqrt{3} }+ \frac{9}{\sqrt{3} } )=\\=\frac{\sqrt{3} }{2}-\frac{15}{\sqrt{3} } =\frac{\sqrt{3} }{2}-5\sqrt{3}=\frac{\sqrt{3}-10\sqrt{3}}{2} =-\frac{9\sqrt{3}}{2}[/tex]
2.
[tex]=(\frac{3\sqrt{2} }{2} -\frac{5\sqrt{2} }{4} )-(3\sqrt{2} +\frac{4\sqrt{2} }{2} )=\\ =\frac{6\sqrt{2}-5\sqrt{2}}{4}-\frac{6\sqrt{2}+4\sqrt{2}}{2} =\\=\frac{\sqrt{2}}{4}-\frac{10\sqrt{2}}{2} =\frac{\sqrt{2}-20\sqrt{2}}{4} =-\frac{19\sqrt{2}}{4}[/tex]
