Answer
$806,400$
Work Step by Step
We know that $n!=n\cdot(n-1)\cdot(n-2)...\cdot2\cdot1.$
Hence,
$\require{cancel}
\dfrac{5!\cdot8!}{3!}\\
=\dfrac{5!\cdot(8\cdot7\cdot6\cdot5\cdot4\cdot3!)}{3!}\\
=\dfrac{5!\cdot(8\cdot7\cdot6\cdot5\cdot4\cdot\cancel{3!})}{\cancel{3!}}\\
=5\cdot4\cdot3\cdot2\cdot1\cdot8\cdot7\cdot6\cdot5\cdot4\\
=806,400$
