Answer
$\color{blue}{p-\dfrac{1}{p}}$
Work Step by Step
RECALL:
$(a-b)(a+b)=a^2-b^2$
Use the formula above with $a=p^{1/2}$ and $b=p^{-1/2}$ to obtain :
$=(p^{1/2})^2 - (p^{-1/2})^2$
Use the rule $(a^m)^n=a^{mn}$ to obtain:
$=p^{(1/2)(2)} - p^{(-1/2)(2)}
\\=p^1 - p^{-1}$
Use the rule $a^{-m} = \dfrac{1}{a^m}$ to obtain:
$=p-\dfrac{1}{p^1}
\\=\color{blue}{p-\dfrac{1}{p}}$
