#### Answer

$a^{23/12}$

#### Work Step by Step

Using the laws of exponents, the given expression, $
a^{2/3}\cdot a^{5/4}
,$ simplifies to
\begin{array}{l}\require{cancel}
a^{\frac{2}{3}+\frac{5}{4}}
\\\\=
a^{\frac{8}{12}+\frac{15}{12}}
\\\\=
a^{\frac{23}{12}}
\\\\=
a^{23/12}
.\end{array}