Question

calculați:
(1×2×3×...×15):(1+2+3+...+15)=​

Answer 1

 

$\displaystyle\bf\\(1\times2\times3\times...\times15):(1+2+3+...+15)=?\\\\1+2+3+...+15=\frac{15(15+1)}{2}=\frac{15\times16}{2}=15\times8=120\\\\120=1\times2\times3\times4\times5\\\\(1\times2\times3\times...\times15):(1+2+3+...+15)=\\\\=\frac{1\times2\times3\times...\times15}{1+2+3+...+15}=\\\\\\=\frac{1\times2\times3\times...\times15}{120}=\\\\\\=\frac{1\times2\times3\times4\times5\times6\times7\times8...\times15}{1\times2\times3\times4\times5}=\\\\\\=\boxed{\bf6\times7\times8\times...\times15}$