Answer
$2a\sqrt[3]{a^2}$
Work Step by Step
The given radical can be written as:
$=\sqrt[3]{8a^3 \cdot a^2}
\\=\sqrt[3]{(2a)^3 \cdot a^2}$
RECALL:
(i) $\sqrt[n]{b^n} = |b|$ when $n$ is even
(ii) $\sqrt[n]{b^n} = b$ when $n$ is odd
The given radical has n=3, which is odd.
Use rule (ii) above to obtain:
$=2a\sqrt[3]{a^2}$