Answer
not a real number
Work Step by Step
Using $a^{\frac{m}{n}}=\sqrt[n]{a^m}$ and the laws of exponents, then,
\begin{align*}
(-4)^{-3/2}
\\\\=
\dfrac{1}{(-4)^{3/2}}
\\\\=
\dfrac{1}{(\sqrt[]{-4})^{3}}
.\end{align*}
Since the radicand is a negative and the index is an even number, then the given expression is not a real number.
