Flexi task due in days?

Igor - You can add a Calculate Date action before your FlexiTask.  You could hardcode X as a number as shown in the first example below. But the better approach would be to pull the number of days from a custom list.  That way you could change the value for X without altering the workflow, as shown in the 2nd example.  In either case, you return the calculated date in a date variable (see bottom of 2nd screen) and then use that date variable in the FlexiTask.