Solve for the indicated variable.
a -c=d-r. for a
a=

You earn a 12% commission for every car you sell. how much is your commission if you sell a $23,000 car?

Solve for x and y: 217x + 131y = 913; 131x + 217y = 827

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.