What is the mathematical expression for the product of 9 and a number

10 points? me . its important ‼️‼️

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.

Which rule describes the composition of transformations that maps △abc to △a”b”c