`1)``\sqrt{12}+4\sqrt{3}-\sqrt{108}-1/4\sqrt{192}`
`=2\sqrt{3}+4\sqrt{3}-6\sqrt{3}-1/4. 8\sqrt{3}`
`=\sqrt{3}(2+4-6-2)`
`=-2\sqrt{3}`
`2)``(\sqrt{15}-2\sqrt{3})/(2-\sqrt{5})+6\sqrt{1/3}+13/(\sqrt{3}-4)`
`=-(\sqrt{3}(\sqrt{5}-2))/(\sqrt{5}-2)+2\sqrt{3}+13/(\sqrt{3}-4)`
`=-\sqrt{3}+2\sqrt{3}+13/(\sqrt{3}-4)`
`=\sqrt{3}+13/(\sqrt{3}-4)`
`=(\sqrt{3}(\sqrt{3}-4)+13)/(\sqrt{3}(\sqrt{3}-4))`
`=(3-4\sqrt{3}+13)/(\sqrt{3}-4)`
`=(16-4\sqrt{3})/(\sqrt{3}-4)`
`=(4(4-\sqrt{3}))/(\sqrt{3}-4)`
`=-4`
