Abigail works as a salesperson at an electronics store and sells phones and phone accessories. abigail earns a $14 commission for every phone she sells and a $3.50 commission for every accessory she sells. on a given day, abigail made a total of $129.50 in commission and sold 7 more accessories than phones. write a system of equations that could be used to determine the number of phones sold and the number of accessories sold. define the variables that you use to write the system.