8.1)

Simplify as much as possible and write as roots:

8.2)

Simplify and write as a single power if possible:

a)

$\sqrt[5]{a^2}\cdot \sqrt{a}\cdot \sqrt[10]{a^{21}}$

b)

$\sqrt{a}\cdot \sqrt[3]{a}\cdot \sqrt[6]{a^7}$

c)

$\sqrt{4^2}\cdot \sqrt[3]{4}\cdot \sqrt[5]{4^3}$

You can find the solutions here.