[tex]\sf-4R-2r+5[/tex] is already in simplest form.
But if you meant to say [tex]\sf-4r-2r+5[/tex], we would combine the first two terms.
Adding/subtracting like terms is the same as adding/subtracting whole numbers.
[tex]\sf-4-2=-6[/tex]
Therefore:
[tex]\sf-4r-2r=-6r[/tex]
Which gives us:
[tex]\boxed{\sf-6r+5}[/tex]
