Question Number 163271 by mnjuly1970 last updated on 05/Jan/22
$$ \\ $$$$\:\:\:\:\:\:{put}\::\:\:{gcd}\left(\:{a}\:,\:{b}\:\right)=\:\left({a},\:{b}\:\right) \\ $$$$\:\:\:\:\:\:\:{if}\:\:\:\left(\:{a}\:,{b}\:\right)=\:\left({a}\:,{c}\:\right)=\:\left({b}\:,{c}\:\right)=\mathrm{1} \\ $$$${prove}\:{that}\::\:\:\left({abc}\:,\:{ab}\:+{ac}\:+{bc}\:\right)=\mathrm{1} \\ $$$$ \\ $$