[tex]\it \sqrt4=2;\ \ \ \sqrt{\dfrac{\ 8^{(2}}{18}}=\sqrt{\dfrac{4}{9}}=\dfrac{\sqrt4}{\sqrt9}=\dfrac{2}{3}\\ \\ \\ Mul\c{\it t}imea\ \ devine:\ \ \ A=\Big\{\sqrt3;\ 2;\ 2\sqrt7;\ 9-\sqrt{12};\ 4-\pi;\ \dfrac{\sqrt5}{2};\ \dfrac{2}{3}\Big\}[/tex]
[tex]\it 2\in\mathbb{Q};\ \ \dfrac{2}{3}\in\mathbb{Q}\\ \\ Elementele\ \ ira\c{\it t}ionale\ \ din\ \ A\ \ sunt:\\ \\ \sqrt3;\ 2\sqrt7;\ 9+\sqrt{12};\ 4-\pi;\ \dfrac{\sqrt5}{2}\\ \\ \sqrt{k}\not\in\mathbb{Q},\ \ pentru\ \ k\ne\ p\breve atrat\ perfect[/tex]
