[tex] 5)n=\big(\frac{5\sqrt3}{\sqrt8}+\frac{3\sqrt3}{5\sqrt2}-\frac{7\sqrt3}{\sqrt2}\big):\sqrt3=\big(\frac{5\sqrt3}{\sqrt8}+\frac{3\sqrt3}{5\sqrt2}-\frac{7\sqrt3}{\sqrt2}\big)\cdot\frac{1}{\sqrt3}=\frac{5\sqrt3}{\sqrt8}\cdot\frac{1}{\sqrt3}\\\\+\frac{3\sqrt3}{5\sqrt2}\cdot\frac{1}{\sqrt3}-\frac{7\sqrt3}{\sqrt2}\cdot\frac{1}{\sqrt3}=\frac{5}{\sqrt8}+\frac{3}{5\sqrt2}-\frac{7}{\sqrt2}
[/tex]
[tex] n\sqrt2=\big(\frac{5}{\sqrt8}+\frac{3}{5\sqrt2}-\frac{7}{\sqrt2}\big)\cdot\sqrt2=\frac{5}{\sqrt8}\cdot\sqrt2+\frac{3}{5\sqrt2}\cdot\sqrt2-\frac{7}{\sqrt2}\cdot\sqrt2\\\\=\frac{5}{\sqrt4}+\frac{3}{5}-7=\frac{5\cdot 5+3\cdot2-7\cdot10}{10}=\frac{-39}{10}\\\\
[/tex]
[tex] -40<-39<-10\text{ }|:10\\
-4<\frac{-39}{10}<-1\Leftrightarrow [n\sqrt2]=-4 [/tex]
[tex] 6) x-\frac{1}{x}=3\\\\
(x-\frac{1}{x})^2=3^2\\\\
x^2-2\cdot x\cdot\frac{1}{x}+\frac{1}{x^2}=9\\\\
x^2+\frac{1}{x^2}-2=9\\\\
x^2+\frac{1}{x^2}=9+2=11\\\\
p\%\text{ din }300=11\Leftrightarrow \frac{p}{100}\cdot 300=11\Leftrightarrow p\cdot3=11\Leftrightarrow p=\frac{11}{3}=3(6) [/tex]
