What do you notice about subtracting 0 from an integer? why does this make sense? what do you notice about adding 0 to an integer? why does this make sense?

Dean and karlene get paid to write songs. dean is paid a one-time fee of $20 plus $80 per day. karlene is paid a one-time fee of $25 plus $100 per day. write an expression to represent how much a producer will pay to hire both to work the same number of days on a song.