Answer
(a) $\displaystyle 4\sqrt{3}$
(b) $\displaystyle \frac{2\sqrt{15}}{5}$
(c) $\displaystyle \frac{8\sqrt[3]{5}}{5}$
Work Step by Step
(a) $\displaystyle \frac{12}{\sqrt{3}}=\frac{12}{\sqrt{3}} \displaystyle \frac{\sqrt{3}}{\sqrt{3}}=\frac{12\sqrt{3}}{3}=4\sqrt{3}$
(b)$\displaystyle \sqrt{\frac{12}{5}}=\frac{\sqrt{12}}{\sqrt{5}} \displaystyle=\frac{\sqrt{12}}{\sqrt{5}} \displaystyle \frac{\sqrt{5}}{\sqrt{5}}=\frac{\sqrt{60}}{5}=\frac{2\sqrt{15}}{5}$
(c) $\displaystyle \frac{8}{\sqrt[3]{5^{2}}}=\frac{8}{5^{2/3}} \displaystyle \frac{5^{1/3}}{5^{1/3}}=\frac{8\sqrt[3]{5}}{5}$