a)
[tex]\dfrac{12}{\sqrt{13+2}}=\dfrac{12}{\sqrt{15}}\cdot\dfrac{\sqrt{15}}{\sqrt{15}}= \dfrac{12\sqrt{15}}{15}= \dfrac{4\sqrt{15}}{5}[/tex]
Ale myślę, że błędnie zapisano przykład i miało być:
[tex]\dfrac{12}{\sqrt{13}+2}=\dfrac{12}{\sqrt{13}+2}\cdot\dfrac{\sqrt{13}-2}{\sqrt{13}-2}= \dfrac{12(\sqrt{13}-2)}{13-4}= \dfrac{^4 {\not}12(\sqrt{13}-2)}{{\not}9_3}= \dfrac{4\sqrt{13}-8}{3}[/tex]
b)
[tex]\dfrac{24}{\sqrt[3]6}\cdot\dfrac{\sqrt[3]{6^2}}{\sqrt[3]{6^2}}=\dfrac{24\sqrt[3]{6^2}}{\sqrt[3]{6^3}}=\dfrac{24\sqrt[3]{36}}{6}=4\sqrt[3]{36}[/tex]
