Unable to install mongoDB

Images to describe your issues is a no-go - they are useless in the forum search engine.

Paste the console output instead.

Ensure your system is fully up-to-date.

Check if you should use AUR packages

if [[ $(pacman-mirrors -G) =~ 'unstable' ]]; then echo 'OK - go ahead'; else  echo 'AUR is no-go';  fi

If you get a no-go from above command switch to unstable branch

sudo pacman-mirrors -aS unstable && sudo pacman -Syyu