Salim has 9 five-dollar bills and ten-dollar bills in his wallet. The total amount in his wallet is $60. This situation can be represented with the system x+y=9 and 5x+10y=60 , where x represents the number of five-dollar bills and y represents the number of ten-dollar bills. Solve the system of equations by graphing. Graph both equations on the coordinate plane even if they represent the same line.