Top part: indeed

Second exercice: that's not correct.

Write:

$\displaystyle \left(4a^{\frac{5}{3}}\right)^{\frac{3}{2}}=\left( 4^{\frac{3}{2}}\right)\cdot\left(a^{\frac{5}{3}} \right)^{\frac{3}{2}}$$\displaystyle =8\cdot a^{\frac{5}{2}}$

Do you understand everything now? Or is it not clear? ...

It's really important that you know al these basic rules!