Odpowiedź:
[tex]a)\ \ \sqrt{\frac{81}{256}}=\frac{\sqrt{81}}{\sqrt{256}}=\frac{9}{16}\\\\\\b)\ \ \sqrt{2,89}=\sqrt{2\frac{89}{100}}=\sqrt{\frac{289}{100}}=\frac{\sqrt{289}}{\sqrt{100}}=\frac{17}{10}=1\frac{7}{10}\\\\\\c)\ \ \sqrt[3]{-\frac{8}{729}}=-\sqrt[3]{\frac{8}{729}}=-\frac{\sqrt[3]{8}}{\sqrt[3]{729}}=-\frac{2}{9}\\\\\\d)\ \ \sqrt[3]{0,064}=\sqrt[3]{\frac{64}{1000}}=\sqrt[3]{\frac{8}{125}}=\frac{\sqrt[3]{8}}{\sqrt[3]{125}}=\frac{2}{5}[/tex]
