Can you guys please help me, I really REALLY need it.

The cost of using a service is $0.25 per min. what equation correctly represents the total cost c, in dollars, for d days of use?

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.

Plz hurry evaluate the expression a+b where a=8 and b=19