12.8 и 12.10

12.8. При \(a,b,x\ge0\):

1. \(\sqrt[3]{3\sqrt[3]{3}}=\sqrt[9]{81}\);
2. \(\sqrt[3]{b\sqrt[4]{b}}=\sqrt[12]{b^5}\);
3. \(\sqrt[5]{x^2\sqrt[6]{x^{13}}}=\sqrt[6]{x^5}\);
4. \(\sqrt[4]{a\sqrt[4]{a^3\sqrt[3]{a}}}=\sqrt[24]{a^{11}}\).

12.10. \((\sqrt m+\sqrt n)(\sqrt[4]{m}+\sqrt[4]{n})(\sqrt[8]{m}+\sqrt[8]{n})(\sqrt[8]{m}-\sqrt[8]{n})=m-n\) при \(m,n\ge0\).