Question

а) $A frac{4}{12} - A frac{4}{11} / A frac{3}{10}$
б) $A frac{4}{15} + A frac{5}{14} / Afrac{3}{15}$
в) $A frac{3}{13} / A frac{3}{15} - A frac{3}{14}$

Answer 1

$A^4_{12}-A^4_{11}:A^3_{10}=11880-7920:720=11880-11=11869\\ A^4_{12}= frac{12!}{(12-4)!}= frac{12!}{8!}= frac{1cdot2cdot3cdot4cdot5cdot6cdot7cdot8cdot9cdot10cdot11cdot12}{1cdot2cdot3cdot4cdot5cdot6cdot7cdot8}=9cdot10cdot11cdot12=11880\\ A^4_{11}= frac{11!}{(11-4)!}= frac{11!}{7!}=7920\\ A^3_{10}= frac{10!}{(10-3)!}= frac{10!}{7!}=720$


$A^4_{15}+A^5_{14}:A^3_{15}=32760+240240:2730=32760+88=32848\\ A^4_{15}= frac{15!}{(15-4)!}= frac{15!}{11!}=32760\\ A^5_{14}= frac{14!}{(14-5)!}= frac{14!}{9!}=240240\\ A^3_{15}= frac{15!}{(15-3)!}= frac{15!}{12!} =2730$


$A^3_{13}:A^3_{15}-A^3_{14}=1716:2730-2184=\\ A^3_{13}= frac{13!}{10!}=1716 \\ A^3_{15}= frac{15!}{12!}= 2730\\ A^3_{14}= frac{14!}{11!}=2184$

Answer 2

а почему непонятным шрифтом написано*

Answer 3

аааа все