[tex]\sqrt{ 7-4\sqrt3}-\frac{1}{5}-\sqrt3=\sqrt{4-2\cdot 2\sqrt3+3}-\frac{1}{5}-\sqrt3=\\\\=\sqrt{(2-\sqrt3)^2}-\frac{1}{5}-\sqrt3=|\underbrace {2-\sqrt3}_{>0}|-\frac{1}{5}-\sqrt3=(2-\sqrt3)-\frac{1}{5}-\sqrt3=\\\\=\frac{9}{5}-2\sqrt3=1,8-2\sqrt3[/tex]