Amplificam fiecare fractie cu radicalul de la numitor.
Rezolvare:
[tex]\displaystyle\bf\\\frac{\sqrt{7}}{4\sqrt{3}}=\frac{\sqrt{7}\times\sqrt{3}}{4\sqrt{3}\times\sqrt{3}} =\frac{\sqrt{7\times3}}{4\sqrt{3\times3}}=\frac{\sqrt{21}}{4\sqrt{9}}=\frac{\sqrt{21}}{4\times3}=\frac{\sqrt{21}}{12}\\\\\\\frac{3}{2\sqrt{5}}=\frac{3\sqrt{5}}{2\sqrt{5}\times\sqrt{5}}=\frac{3\sqrt{5}}{2\sqrt{5\times5}}=\frac{3\sqrt{5}}{2\sqrt{25}}=\frac{3\sqrt{5}}{2\times5}=\frac{3\sqrt{5}}{10}\\\\\\\frac{\sqrt{7}}{\sqrt{3}}=\frac{\sqrt{7}\times\sqrt{3}}{\sqrt{3}\times\sqrt{3}} =\frac{\sqrt{21}}{3}[/tex]
