Answer
$a^{-4}b^9$
Work Step by Step
Here, we have $(a^5 b^4)^2=(a^5)^2 (b^4)^2$
Here, we have
$(a^5)^2 = a^{10}$ and $(b^4)^2=b^8$
Now,
$a^{10}b^{8}=a^{14} b^{-1}=e$
This gives; $e=\dfrac{a^{10}b^{8}}{a^{14} b^{-1}}=a^{10-14} b^{8-(-1)}$
Hence, $e=a^{-4}b^9$