The Arial font is get installed by
ttf-mscorefonts-installer and the David font is available in
Open a terminal and do this command to get them
sudo apt-get install ttf-mscorefonts-installer culmus
Or using Software center:
If you want to install only the David font (culmus package includes some other fonts too), you can download that font from the link below
Download link for David font only
Download it and copy the font file in the
.fonts directory in your home. This directory is hidden by default. Use
H to reveal the hidden files and folders.
If the directory does not exists already, create one with name .fonts and copy the file in that directory.
Note: You have to accept the EULA when installing the ttf-mscorefonts-installer package. Use Tab for navigation in the terminal.
Arial is installed by ttf-mscorefonts-installer as described in the package's description
David font is in the culmus package as described by the package's file list