If 2x-5 is a factor of the poloynomial 4x^4-28x^3+59x^2-23x+c what value does c have?

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.