Answer
$\color{blue}{p\sqrt[4]{p}}$
Work Step by Step
RECALL:
(1) $a^{m/n}=\sqrt[n]{a^m} = (\sqrt[n]{a})^m$
(2) For $a\gt0$, $\sqrt[n]{a^n} = n$
Use rule (1) above to obtain:
$p^{5/4}
\\= \sqrt[4]{p^5}
\\=\sqrt[4]{p^4(p)}$
Use rule (2) above to obtain:
$=\color{blue}{p\sqrt[4]{p}}$
