## Intermediate Algebra (12th Edition)

$\frac{1}{a^{5}}$
According to the product rule for exponents, $a^{m}\times a^{n}=a^{m+n}$ (where $m$ and $n$ are integers and $a$ is a real number). Therefore, $a^{-3}a^{2}a^{-4}=a^{-3+2+(-4)}=a^{-5}$. According to the definition of negative exponents, $a^{-n}=\frac{1}{a^{n}}$ (where $a\ne0$). Therefore, $a^{-5}=\frac{1}{a^{5}}$.