Answer
64
Work Step by Step
$\displaystyle \frac{4^{9/4}\cdot 4^{-7/4}}{4^{-10/4}}=$
...use: $a^{m}\cdot a^{n}=a^{m+n}$ and $\displaystyle \frac{a^{m}}{a^{n}}=a^{m-n}$...
$=4^{9/4-7/4-(-10/4)}$
$=4^{(9-7+10)/4}$
$=4^{12/4}$
$=4^{3}=64$