Precalculus (10th Edition)

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