For the function F. g. h. I. j. k f=xy+xy+xy

The function $f$ can be simplified by combining like terms.

Step 1: Combine like terms
The given function is:
$f = xy + xy + xy$
Since all terms are identical ($xy$), we can add their coefficients:
$f = (1+1+1)xy$
$f = 3xy$

The simplified function is:
$\boxed{f = 3xy}$