Question

Помогите
100!/99!-99!/98!
50!/48!-30!/98!

Answer 1

$\frac{100!}{99!}-\frac{99!}{98!}=\frac{99!\, \cdot \, 100}{99!}-\frac{98!\, \cdot 99}{98!}=100-99=1\\\\\\\frac{50!}{48!}-\frac{30!}{28!}=\frac{48!\, \cdot 49\cdot 50}{48!}-\frac{28!\, \cdot \, 29\cdot 30}{28!}=49\cdot 50-29\cdot 30=2450-870=1580$