Question

Решить факториал 8!−7!/6!

Answer 1

$\dfrac{8!\, -7!}{6!}=\dfrac{6!\, \cdot 7\cdot 8\, -\, 6!\, \cdot 7}{6!}=\dfrac{6!\, \cdot (7\cdot 8-7)}{6!}=7\cdot 8-7=7\cdot (8-1)=\\\\\\=7\cdot 7=49\\\\\\\boxed {\; n!=(n-1)!\, \cdot n\; }$