#### Answer

$a-a^{2}$

#### Work Step by Step

$a^{-\frac{1}{4}}(a^{\frac{5}{4}}-a^{\frac{9}{4}})$
=$a^{-\frac{1}{4}}(a^{\frac{5}{4}})-a^{-\frac{1}{4}}(a^{\frac{9}{4}})$
=$(a^{-\frac{1}{4}+\frac{5}{4}})-(a^{-\frac{1}{4}+\frac{9}{4}})$
=$(a^{\frac{-1+5}{4}})-(a^{\frac{-1+9}{4}})$
=$(a^{\frac{4}{4}})-(a^{\frac{8}{4}})$
=$(a^{1})-(a^{2})$
=$a-a^{2}$